HP 12C Platinum Solutions Handbook Pt_solutions Handbook_English_E C00367123

User Manual: HP hp 12c pt_solutions handbook_English_E

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© Hewlett-Packard Development Company, L.P. rev. 03.04
HP 12C Platinum
Solutions Handbook
HP would like to thank the following for their contribution:
Tony Hutchins, Wellington, NZ
Luiz Vieira, UNIPAC, Brazil
Gene Wright, Lipscomb University, USA
NOTICE
Hewlett-Packard Company makes no express or implied warranty with regard to the keystroke
procedures and program material offered or their merchantability or their fitness for any
particular purpose. The keystroke procedures and program material are made available
solely on an "as is" basis, and the entire risk as to their quality and performance is with the
user. Should the keystroke procedures or program material prove defective, the user (and not
Hewlett-Packard Company nor any other party) shall bear the entire cost of all necessary
correction and all incidental and consequential damages. Hewlett-Packard Company shall not
be liable for any incidental or consequential damages in connection with or arising out of the
furnishing, use, or performance of the keystroke procedures or program material.
2
Introduction
About This Handbook
This HP 12C Platinum Solutions Handbook has been designed to supplement the HP 12C
Platinum Owner's Handbook by providing a variety of applications in the financial area.
Programs and/or step-by-step keystroke procedures with corresponding examples in each
specific topic are explained. We hope that this book will serve as a reference guide to
many of your problems and will show you how to redesign our examples to fit your
specific needs.
This book expands the original HP-12C Solutions handbook with additional solutions in
algebraic mode. It contains the same RPN program keystrokes and RPN step-by-step
procedure keystrokes, in columns headed “12c platinum / 12C RPN Keystrokes”. The
alternative algebraic keystrokes are tablulated under “12c platinum ALG Keystrokes”. In
program listings the “Display” columns show the keycodes as seen on the HP 12C
Platinum.
Appendix A also contains algebraic listings for all the RPN programs given in Part III of
the HP 12C Platinum Owner’s Handbook.
Presentation of Algebraic and RPN
The conventions used to differentiate between RPN and ALG mode are:
1. Program Listings
Complete and separate listings are given for all programs. They appear side by side
in two columns with RPN on the left and Algebraic on the right.
2. Step-by-Step Keystroke Procedures
As for programs separate columns are used, with the RPN keystrokes on the left
and the Algebraic keystrokes on the right.
3. Program Instructions
Program instruction steps are generally the same for both modes. Any differences
are shown by clearly framing alternative steps and annotating the step or steps in
the first frame as RPN, and those in the second as ALG.
4. Text
Occasionally there are small differences which need to be indicated in the text
Introduction 3
itself and the ALG alternative is then indicated parenthetically.
5. Usage of \(³)
To activate the ³ key it is sufficient just to press \, with the HP 12C
Platinum in ALG mode. In step-by-step and program instructions where the only
difference between the modes is that \ is used in RPN mode and ³ is used
in ALG mode, \(³) has been used to indicate both alternatives.
Using the RPN Programs on the HP-12C
Apart from GTO instructions, the keystrokes given in this book are exactly the same for
the HP 12C Platinum and the HP-12C. There are two notational differences to bear in
mind when typing the RPN programs into the HP-12C:
1. One keycode, for F, is different.
2. Line numbers tabulated as 000 to 099 refer to lines displayed as 00 to 99 on the
HP-12C. The relevant two digit line numbers should be used when typing GTO
instructions on the HP-12C.
Notes:
1. All display columns in the examples this book show 2 decimals. This is set by
pressing f2.
All programs that do rounding, amortization or depreciation will give slightly
different answers if other than 2 decimals are showing.
2. Three of the original programs have been updated:
a. The last program in the Real Estate section (ATNCPR) now takes the capital
gains tax rate as a separate input, and an extra example has been added
showing a different type of tax basis.
b. In the Personal Finance section the IRA program now handles explicit
inflation input and withdrawal tax rate input and the Stock Portfolio program
handles stock prices with decimal fractions rather than fractions expressed in
terms of eighths.
3. Market data (i.e.: interest rates; real estate values, growth rates and rents; taxes;
expenses; etc.) used in the examples in this book do not necessarily represent
typical current actual data, or reflect recent market trends.
4
Contents
Introduction ........................................................................................................................ 2
About This Handbook..................................................................................................... 2
Presentation of Algebraic and RPN ................................................................................2
Using the RPN Programs on the HP-12C .......................................................................3
Contents.............................................................................................................................. 4
Real Estate..........................................................................................................................7
Refinancing.....................................................................................................................7
Wrap-Around Mortgage .................................................................................................8
Income Property Cash Flow Analysis........................................................................... 12
Before-Tax Cash Flows ............................................................................................ 12
Before-Tax Reversions (Resale Proceeds)................................................................ 13
After-Tax Cash Flows...............................................................................................14
After-Tax Net Cash Proceeds of Resale.................................................................... 19
Lending............................................................................................................................. 24
Loan With a Constant Amount Paid Towards Principal ............................................... 24
Add-On Interest Rate Converted to APR......................................................................25
APR Converted to Add-On Interest Rate......................................................................26
Add-On Rate Loan with Credit Life .............................................................................27
Interest Rebate - Rule of 78's........................................................................................ 30
Graduated Payment Mortgages..................................................................................... 32
Variable Rate Mortgages .............................................................................................. 36
Skipped Payments......................................................................................................... 38
Savings ............................................................................................................................. 40
Initial Deposit with Periodic Deposits .......................................................................... 40
Number of Periods to Deplete a Savings Account or to Reach a Specified Balance ....41
Periodic Deposits and Withdrawals .............................................................................. 42
Savings Account Compounded Daily ........................................................................... 44
Compounding Periods Different From Payment Periods.............................................. 46
Investment Analysis..........................................................................................................49
Lease vs. Purchase ........................................................................................................ 49
Break-Even Analysis .................................................................................................... 53
Operating Leverage ...................................................................................................... 59
Profit and Loss Analysis............................................................................................... 61
Securities and Options ...................................................................................................... 65
After-Tax Yield ............................................................................................................ 65
Discounted Notes.......................................................................................................... 67
Black-Scholes Formula for Valuing European Options................................................ 69
Contents 5
Forecasting........................................................................................................................74
Simple Moving Average ...............................................................................................74
Seasonal Variation Factors Based on Centered Moving Averages ...............................78
Gompertz Curve Trend Analysis...................................................................................83
Forecasting with Exponential Smoothing .....................................................................87
Pricing Calculations ..........................................................................................................92
Markup and Margin Calculations..................................................................................92
Calculations of List and Net prices With Discounts......................................................95
Statistics............................................................................................................................98
Curve Fitting .................................................................................................................98
Exponential Curve Fit ...............................................................................................98
Logarithmic Curve Fit.............................................................................................102
Power Curve Fit ......................................................................................................104
Standard Error of the Mean.........................................................................................105
Mean, Standard Deviation, Standard Error for Grouped Data ....................................106
Chi-Square Statistics ...................................................................................................109
Normal Distribution ....................................................................................................112
Covariance ..................................................................................................................114
Permutations ...............................................................................................................116
Combinations ..............................................................................................................117
Random Number Generator ........................................................................................119
Personal Finance .............................................................................................................121
Homeowners Monthly Payment Estimator .................................................................121
Tax-Free Individual Retirement (IRA) or Keogh Plan................................................124
Stock Portfolio Evaluation and Analysis.....................................................................127
Canadian Mortgages .......................................................................................................131
Periodic Payment Amount ..........................................................................................131
Number of Periodic Payments to Fully Amortize a Mortgage ....................................132
Effective Interest Rate (Yield) ....................................................................................132
Balance Remaining at End of Specified Period...........................................................132
Miscellaneous .................................................................................................................134
Learning Curve for Manufacturing Costs ...................................................................134
Queuing and Waiting Theory......................................................................................138
Appendix A : Programs from Part III of the Owner's Handbook ....................................145
About this Appendix ...................................................................................................145
Algebraic Mode Programs ..........................................................................................146
Section 12: The Rent or Buy Decision....................................................................146
Section 13: Straight-Line Depreciation...................................................................147
Section 13: Declining-Balance Depreciation ..........................................................148
Section 13: Sum-of-the-Years-Digits Depreciation.................................................149
Section 13: Full- and Partial- Year Depreciation with Crossover ...........................150
Section 14: Lease with Advance Payments - Solving For Payment ........................151
Section 14: Lease with Advance Payments - Solving For Yield .............................151
Section 14: Advance Payments With Residual - Solving for Payment ...................152
6 Contents
Section 15: Nominal Rate Converted to Effective Rate......................................... 152
Section 16: 30/360 Day Basis Bonds ..................................................................... 153
Section 16: Annual Coupon Bonds ......................................................................... 154
Appendix B: Formulas Used........................................................................................... 155
Real Estate.................................................................................................................. 155
Wrap-Around Mortgage ......................................................................................... 155
After-Tax Cash Flows.............................................................................................155
After-Tax Net Cash Proceeds of Resale.................................................................. 155
Lending....................................................................................................................... 156
Loans With a Constant Amount Paid Towards Principal........................................ 156
Add-On Interest Rate to APR ................................................................................. 156
Add-On to APR with Credit Life............................................................................ 156
Rule of 78's Rebate ................................................................................................. 156
Graduated Payment Mortgage ................................................................................ 157
Skipped Payments................................................................................................... 157
Savings ....................................................................................................................... 158
Compounding Periods Different From Payment Periods........................................ 158
Investment Analysis.................................................................................................... 158
Lease vs. Purchase .................................................................................................. 158
Break-Even Analysis and Operating Leverage ....................................................... 158
Profit and Loss Analysis ......................................................................................... 158
Securities and Options ................................................................................................ 159
Discounted Notes.................................................................................................... 159
Black-Scholes Formula for Valuing European Options.......................................... 159
Forecasting ................................................................................................................. 160
Simple Moving Average ......................................................................................... 160
Seasonal Variation Factors Based on a Centered Moving Average ........................ 160
Gompertz Curve Trend Analysis ............................................................................ 160
Forecasting With Exponential Smoothing .............................................................. 161
Pricing Calculations.................................................................................................... 161
Markup and Margin Calculations ........................................................................... 161
Calculations of List and Net Prices with Discounts................................................ 162
Statistics...................................................................................................................... 162
Exponential Curve Fit............................................................................................. 162
Logarithmic Curve Fit ............................................................................................163
Power Curve Fit...................................................................................................... 163
Standard Error of the Mean.....................................................................................163
Mean, Standard Deviation, Standard Error for Grouped Data ................................ 163
Personal Finance......................................................................................................... 164
Tax-Free Retirement Account (IRA) or Keogh Plan .............................................. 164
Stock Portfolio Evaluation and Analysis ................................................................ 164
Portfolio beta coefficient: ....................................................................................... 164
Canadian Mortgages ................................................................................................... 164
Miscellaneous ............................................................................................................. 165
Learning Curve for Manufacturing Cost................................................................. 165
Queuing and Waiting Theory.................................................................................. 165
Subject Index .................................................................................................................. 166
7
Real Estate
Refinancing
It can be mutually advantageous to both borrower and lender to refinance an existing
mortgage which has an interest rate substantially below the current market rate, with a
loan at a below-market rate. The borrower has the immediate use of tax-free cash, while
the lender has substantially increased debt service on a relatively small cash outlay.
To find the benefits to both borrower and lender:
1. Calculate the monthly payment on the existing mortgage.
2. Calculate the monthly payment on the new mortgage.
3. Calculate the net monthly payment received by the lender (and paid by the borrower)
by adding the figure found in Step 1 to the figure found in Step 2.
4. Calculate the Net Present Value (NPV) to the lender of the net cash advanced.
5. Calculate the yield to the lender as an IRR.
6. Calculate the NPV to the borrower of the net cash received.
Example: An investment property has an existing mortgage which originated 8 years ago
with an original term of 25 years, fully amortized in level monthly payments at 6.5%
interest. The current balance is $133,190.
Although the going current market interest rate is 11.5%, the lender has agreed to
refinance the property with a $200,000, 17 year, level-monthly-payment loan at 9.5%
interest.
What are the NPV and effective yield to the lender on the net amount of cash actually
advanced?
What is the NPV to the borrower on this amount if he can earn a 15.25% equity yield rate
on the net proceeds of the loan?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
gÂ
fCLEARG
17gA
6.5gC
133190$
P?0
gÂ
fCLEARG
17gA
6.5gC
133190$
P?0
-1,080.33
Monthly payment on
existing mortgage
received by lender.
8 Real Estate
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
9.5gC
200000Þ$
P
9.5gC
200000Þ$
P
1,979.56
Monthly payment on
new mortgage.
:0+P +:0P 899.23 Net monthly payment (to
lender).
:$ :$
133190+?0 +133190³?0 -66,810.00 Net amount of cash
advanced (by lender).
11.5gC$ 11.5gC$$ -80,425.02 Present value of net
monthly payment.
:0- -:0³ -13,615.02 NPV to lender of net
cash advanced.
:0$¼ :0$¼
12§ §12³ 14.83 % nominal yield (IRR).
15.25gC$ 15.25gC$$ -65,376.72 Present value of net
monthly payment at
15.25%.
:0- -:0³ 1,433.28 NPV to borrower.
Wrap-Around Mortgage
A wrap-around mortgage is essentially the same as a refinancing mortgage, except that the
new mortgage is granted by a different lender, who assumes the payments on the existing
mortgage, which remains in full force. The new (second) mortgage is thus "wrapped
around" the existing mortgage. The "wrap-around" lender advances the net difference
between the new (second) mortgage and the existing mortgage in cash to the borrower,
and receives as net cash flow, the difference between debt service on the new (second)
mortgage and debt service on the existing mortgage.
When the terms of the original mortgage and the wrap-around are the same, the
procedures in calculating NPV and IRR to the lender and NPV to the borrower are exactly
the same as those presented in the preceding section on refinancing.
Example 1: A mortgage loan on an income property has a remaining balance of
$200,132.06. When the load originated 8 years ago, it had a 20 year term with full
amortization in level monthly payments at 6.75% interest.
A lender has agreed to "wrap" a $300,000 second mortgage at 10%, with full amortization
in level monthly payments over 12 years. What is the effective yield (IRR) to the lender
on the net cash advanced?
Real Estate 9
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
gÂ
fCLEARG
20\
8-gA
gÂ
fCLEARG
20-
8³gA
144.00
Total number of months
remaining in original loan
(into n).
6.75gC 6.75gC 0.56 Monthly interest rate (into i).
200132.06$ 200132.06$ 200,132.06 Loan amount (into PV).
P?0 P?0 -2,031.55 Monthly payment on existing
mortgage (calculated).
10gC 10gC 0.83 Monthly interest on wrap-
around.
300000Þ$ 300000Þ$ -300,000.00 Amount of wrap-around (into
PV).
P P 3,585.23 Monthly payment on wrap-
around (calculated).
:0+P +:0P 1,553.69 Net monthly payment
received (into PMT).
:$ :$
200132.06+$ +200132.06$ -99,867.94 Net cash advanced (into PV).
¼12§ ¼§12³ 15.85 Nominal yield (IRR) to lender
(calculated).
Sometimes the wrap around mortgage will have a longer payback period than the original
mortgage, or a balloon payment may exist.
PV
1
P
M
T
2 for n2 Years
B
AL
(+)
PV
2
P
M
T
1 for n1 Years
(–)
... ...
10 Real Estate
Where:
n1 = number of years remaining in original mortgage
PMT1 = yearly payment of original mortgage
PV1 = remaining balance of original mortgage
n2 = number of years in wrap-around mortgage
PMT2 = yearly payment of wrap-around mortgage
PV2 = total amount of wrap-around mortgage
BAL = balloon payment
Example 2: A customer has an existing mortgage with a balance of $125,010, a
remaining term of 200 months, and a $1051.61 monthly payment. He wishes to obtain a
$200,000, 9 ½% wrap-around with 240 monthly payments of $1681.71 and a balloon
payment at the end of the 240th month of $129,963.35. If you, as a lender, accept the
proposal, what is your rate of return?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g gÂ
fCLEARG fCLEARG
200000Þ\ 200000Þ
125010+gJ +125010gJ -74,990.00 Net investment.
1051.61Þ\ 1051.61Þ
1681.71+ +1681.71gK 630.10 Net cash flow
received by lender.
$125010
$ -200000
240 mos.
200 mos.
$ 129963.35
$1681.71 $1681.71 $1681.71
$ -1051.61 $ -1051.61
... ...
Real Estate 11
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
gK99ga
~gK
~ga
~gK
2ga
99ga
~gK
~ga
~gK
2ga
The above cash flow
occurs 200 times.
gFgK 1681.71gK 1,681.71 Next cash flow
received by lender.
39ga 39ga 39.00 Cash flow occurs 39
times.
~129963.35+ ~+129963.35
gK gK 131,645.06 Final cash flow.
fL12§ fL§12³ 11.84 Rate of return to
lender.
If you, as a lender, know the yield on the entire transaction, and you wish to obtain the
payment amount on the wrap-around mortgage to achieve this yield, use the following
procedure. Once the monthly payment is known, the borrower's periodic interest rate may
also be determined.
1. Press the g and press fCLEARG.
2. Key in the remaining periods of the original mortgage and press n.
3. Key in the desired annual yield and press gC.
4. Key in the monthly payment to be made by the lender on the original mortgage and
press ÞP.
5. Press $.
6. RPN: Key in the net amount of cash advanced and press +Þ$.
6. ALG: Press +, key in the net amount of cash advanced and press ³Þ$.
7. Key in the total term of the wrap-around mortgage and press n.
8. If a balloon payment exists, key it in and press M.
9. Press P to obtain the payment amount necessary to achieve the desired yield.
10. Key in the amount of the wrap-around mortgage and press Þ$¼ to obtain the
borrower's periodic interest rate.
Example 3: Your firm has determined that the yield on a wrap-around mortgage should
be 12% annually. In the previous example, what monthly payment must be received to
achieve this yield on a $200,000 wrap-around? What interest rate is the borrower paying?
12 Real Estate
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g gÂ
fCLEARG fCLEARG
200n12gC 200n12gC Number of periods and
monthly interest rate.
1051.61ÞP 1051.61ÞP Monthly payment.
$74990+ $+74990³
Þ$ Þ$ -165,776.92 Present value of
payments plus cash
advanced.
240n 240n
129963.35MP 129963.35MP 1,693.97 Monthly payment
received by lender.
200000Þ$¼ 200000Þ$¼
12§ §12³ 9.58 Annual interest rate paid
by borrower.
Income Property Cash Flow Analysis
Before-Tax Cash Flows
The before-tax cash flows applicable to real estate analysis and problems are:
• Potential Gross Income
• Effective Gross Income
• Net Operating Income (also called Net Income Before Recapture)
• Cash Throw-off to Equity (also called Gross Spendable Cash)
The derivation of these cash flows follows a set sequence:
1. Calculate Potential Gross Income by multiplying the rent per unit times the number
of units, times the number of rental payment periods per year. This gives the rental
income the property would generate if it were fully occupied.
2. Deduct Allowance for Vacancy and Rental Loss. This is usually expressed as a
percentage. The result is Rent Collections (which is also Effective Gross Income if
there is no "Other Income").
3. Add "Other Income" such as receipts from concessions (laundry equipment, etc.),
produced from sources other than the rental office space. This is Effective Gross
Income.
4. Deduct Operating Expenses. These are expenditures the landlord-investor must
make, by contract or custom, to preserve the property and keep in capable of
producing the gross income. The result is the Net Operating Income.
5. Deduct Annual Debt Service on the mortgage. This produces Cash Throw-Off to
Equity.
Real Estate 13
Thus:
Effective Gross Income =Potential Gross Income - Vacancy Loss + Other Income.
Net Operating Income =Effective Gross Income - Operating Expenses.
Cash Throw-Off =Net Operating Income - Annual Dept Service.
Example: A 60 unit apartment building has rentals of $250 per unit per month. With a
5% vacancy rate, the annual operating cost is $76,855.
The property has just been financed with a $700,000 mortgage, fully amortized in a level
monthly payments at 11.5% over 20 years.
a. What is the Effective Gross Income?
b. What is the Net Operating Income?
c. What is the Cash Throw-Off to Equity?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
gÂ
fCLEARG
60\
gÂ
fCLEARG
60§
250§12§ 250§12- 180,000.00 Potential Gross Income.
5b- 5b- 171,000.00 Effective Gross Income.
76855- 76855³ 94,145.00 Net Operating Income.
20gA 20gAd
11.5gC 11.5gCd
700000$ 700000$
P12§ P§12+ -89,580.09 Annual Debt Service.
+ ~³ 4,564.91 Cash Throw-Off.
Before-Tax Reversions (Resale Proceeds)
The reversion receivable at the end of the income projection period is usually based on
forecast or anticipated resale of the property at that time. The before tax reversion amount
applicable to real estate analysis and problems are:
• Sale Price.
• Cash Proceeds of Resale.
• Outstanding Mortgage Balance.
• Net Cash Proceeds of Resale to Equity.
The derivation of these reversions is as follows:
1. Forecast or estimate Sales Price. Deduct sales and Transaction Costs. The result is
the Proceeds of Resale.
14 Real Estate
2. Calculate the Outstanding Balance of the Mortgage at the end of the Income
Projection Period and subtract it from Proceeds of Resale. The result is Net Cash
Proceeds of Resale.
Thus:
Cash Proceeds of Resale = Sales Price - Transaction Costs.
Net Cash Proceeds of Resale = Cash Proceeds of Resale - Outstanding Mortgage Balance.
Example: The apartment property in the preceding example is expected to be resold in 10
years. The anticipated resale price is $800,000. The transaction costs are expected to be
7% of the resale price. The mortgage is the same as that indicated in the preceding
example.
• What will the Mortgage Balance be in 10 years?
• What are the Cash Proceeds of Resale and Net Cash Proceeds of Resale?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g gÂ
fCLEARG fCLEARG
20gA 20gA 240.00 Mortgage term.
11.5gC 11.5gC 0.96 Mortgage rate.
700000$ 700000$ Property value.
P P -7,465.01 Monthly payment.
10gA 10gA 120.00 Projection period.
M MM -530,956.57 Mortgage balance in 10 years.
800000\ 800000- Estimated resale.
7b- 7b+ 744,000.00 Cash Proceeds of Resale.
+ ~³ 213,043.43 Net Cash Proceeds of Resale.
After-Tax Cash Flows
The After-Tax Cash Flow (ATCF) is found for the each year by deducting the Income
Tax Liability for that year from the Cash Throw Off.
Where Taxable Income = Net Operating Income - interest - depreciation,
Tax Liability = Taxable Income x Marginal Tax Rate,
and After Tax Cash Flow = Cash Throw Off - Tax Liability.
The After-Tax Cash Flow for the initial and successive years may be calculated by the
following HP 12C Platinum program. This program calculates the Net Operating Income
using the Potential Gross Income, operational cost and vacancy rate. The Net Operating
Real Estate 15
income is readjusted each year from the growth rates in Potential Gross Income and
operational costs.
The user is able to change the method of finding the depreciation from declining balance
to straight line. To make the change, key in fV at line 032 (ALG: 026) of the
program in place of f#.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
0 001, 0 0 001, 0
n 002, 11 n 002, 11
?1 003, 44 1 1 003, 1
:7 004, 45 7 2 004, 2
Æ 005, 26 f! 005, 42 11
2 006, 2 ?0 006, 44 0
z 007, 10 :5 007, 45 5
?7 008, 44 7 n 008, 11
1 009, 1 :¼ 009, 45 12
?+1 010,44 40 1 :6 010, 45 6
1 011, 1 ¼ 011, 12
2 012, 2 d 012, 33
f! 013, 42 11 ?6 013, 44 6
?0 014, 44 0 d 014, 33
:5 015, 45 5 :$ 015, 45 13
n 016, 11 :4 016, 45 4
:¼ 017, 45 12 $ 017, 13
:6 018, 45 6 d 018, 33
¼ 019, 12 ?4 019, 44 4
d 020, 33 d 020, 33
?6 021, 44 6 gm 021, 43 35
d 022, 33 g(030 022,43,33,030
:$ 023, 45 13 1 023, 1
:4 024, 45 4 ?+1 024,44 40 1
$ 025, 13 :1 025, 45 1
d 026, 33 f# 026, 42 25
?4 027, 44 4 ?-0 027,44 30 0
d 028, 33 0 028, 0
gm 029, 43 35 g(009 029,43,33,009
g(036 030,43,33,036 :2 030, 45 2
:1 031, 45 1 - 031, 30
f# 032, 42 25 :.0 032,45 48 0
?-0 033,44 30 0 b 033, 25
0 034, 0 - 034, 30
g(017 035,43,33,017 :3 035, 45 3
16 Real Estate
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
n 036, 11 ³ 036, 36
:2 037, 45 2 ?+0 037,44 40 0
:8 038, 45 8 + 038, 40
b 039, 25 :P 039, 45 14
?+2 040,44 40 2 gA 040, 43 11
d 041, 33 ³ 041, 36
:.0 042,45 48 0 :7 042, 45 7
b 043, 25 b 043, 25
- 044, 30 ?§0 044,44 20 0
:3 045, 45 3 d 045, 33
:9 046, 45 9 - 046, 30
b 047, 25 :0 047, 45 0
?+3 048,44 40 3 ³ 048, 36
d 049, 33 :1 049, 45 1
- 050, 30 gu 050, 43 31
1 051, 1 ~ 051, 34
:7 052, 45 7 t 052, 31
?§0 053,44 20 0 :2 053, 45 2
- 054, 30 + 054, 40
§ 055, 20 :8 055, 45 8
:P 056, 45 14 b 056, 25
1 057, 1 ³ 057, 36
2 058, 2 ?2 058, 44 2
§ 059, 20 :3 059, 45 3
+ 060, 40 + 060, 40
:0 061, 45 0 :9 061, 45 9
- 062, 30 b 062, 25
:1 063, 45 1 ³ 063, 36
gu 064, 43 31 ?3 064, 44 3
~ 065, 34 g(001 065,43,33,001
t 066, 31 fs
g(009 067,43,33,009
fs
REGISTERS
n: Used i: Annual % PV: Used PMT: Monthly
FV: 0 R0: Used R1: Counter R2: PGI
R3: Oper. cost R4: Dep. value R5: Dep. Life R6: Factor (DB)
R7: Tax Rate R8: % gr. (PGI) R9: % gr. (op) R.0: Vacancy rt.
Real Estate 17
Program Instructions:
1. Press g and press fCLEARH.
2. Key in loan values:
● Key in annual interest rate and press gC
● Key in principal to be paid and press $
● Key in monthly payment and press ÞP
(If any of the values are not known, they should be solved for.)
3. Key in Potential Gross Income (PGI) and press ?2.
4. Key in Operational cost and press ?3.
5. Key in depreciable value and press ?4.
6. Key in depreciable life and press ?5.
7. Key in factor (for declining balance only) and press ?6.
8. Key in the Marginal Tax Rate (as a percentage) and press ?7.
9. Key in the growth rate in Potential Gross Income (0 for no growth) and press
?8.
10. Key in the growth rate in operational cost (0 if no growth) and press ?9.
11. Key in the vacancy rate (0 for no vacancy rate) and press ?.0.
12. RPN: Key in the desired depreciation function at line 032 in the program.
12. ALG: Key in the desired depreciation function at line 026 in the program.
13. Press t to compute ATCF. The display will pause showing the year and then
will stop with the ATCF for that year. The Y-register contains the year.
14. Continue pressing t to compute successive After-Tax Cash Flows.
Example 1: A triplex was recently purchased for $100,000 with a 30 year loan at 12.25%
and a 20% down payment. Not including a 5% annual vacancy rate, the potential gross
income is $9,900 with an annual growth rate of 6%. Operating expenses are $3,291.75
with a 2.5% growth rate. The depreciable value is $75,000 with a projected useful life of
$20 years. Assuming a 125% declining balance depreciation, what are the After-Tax Cash
Flows for the first 10 years if the investors Marginal Tax Rate is 35%?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g gÂ
fCLEARH fCLEARH
100000\ 100000-
20b-$ 20b$ 80,000.00 Mortgage amount.
12.25gC 12.25gC 1.02 Monthly interest rate.
30gA 30gA 360 Mortgage term.
P PP -838.32 Monthly payment.
9900?2 9900?2 9,900.00 Potential Gross Income.
18 Real Estate
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
3291.75?3 3291.75?3 3,291.75 1st year operating cost.
75000?4 75000?4 75,000.00 Depreciable value.
20?5 20?5 20.00 Useful life.
125?6 125?6 125.00 Declining balance factor.
35?7 35?7 35.00 Marginal Tax Rate.
6?8 6?8 6.00 Potential Gross Income
growth rate.
2.5?9 2.5?9 2.50 Operating cost growth.
5?.0 5?.0 5.00 Vacancy rate.
t t 1.00 Year 1
-1,020.88
A
TC
F
1
t t 2.00 Year 2
-822.59
A
TC
F
2
t t 3.00 Year 3
-598.85
A
TC
F
3
t t 4.00 Year 4
-348.94
A
TC
F
4
t t 5.00 Year 5
-72.16
A
TC
F
5
t t 6.00 Year 6
232.35
A
TC
F
6
t t 7.00 Year 7
565.48
A
TC
F
7
t t 8.00 Year 8
928.23
A
TC
F
8
t t 9.00 Year 9
1,321.62
A
TC
F
9
t t 10.00 Year 10
1,746.81
A
TC
F
10
Example 2: An office building was purchased for $1,400,000. The value of depreciable
improvements is $1,200,000 with a 35 year economic life. Straight line depreciation will
be used. The property is financed with a $1,050,000 loan. The terms of the loan are 9.5%
interest and $9,173.81 monthly payments for 25 years. The office building generates a
Potential Gross Income of $175,200 which grows at a 3.5% annual rate. The operating
cost is $40,296.00 with a 1.6% annual growth rate. Assuming a Marginal Tax Rate of
50% and a vacancy rate of 7%, what are the After-Tax Cash Flows for the first 5 years?
Real Estate 19
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
gÂ
fCLEARH
1050000$
9173.81ÞP
9.5gC
25gA
gÂ
fCLEARH
1050000$
9173.81ÞP
9.5gC
25gA
175200?2 175200?2 175,200.00 Potential Gross
Income.
40296?3 40296?3 40,296.00 1st year operating
cost.
1200000?4 1200000?4 1,200,000.00 Depreciable value.
35?5 35?5 35.00 Depreciable life.
50?7 50?7 50.00 Marginal tax rate.
3.5?8 3.5?8 3.50 Potential Gross
Income growth rate.
1.6?9 1.6?9 1.60 Operating cost
growth rate.
7?.0 7?.0 7.00 Vacancy rate.
g(031 g(025 7.00 Go to dep. step.
fsfV fsfV 032, 42 23
026, 42 23 RPN:Change to SL
ALG:depreciation
fst fst 1.00 Year 1
18,021.07 ATCF1
t t 2.00 Year 2
20,014.26 ATCF2
t t 3.00 Year 3
22,048.90 ATCF3
t t 4.00 Year 4
24,123.14 ATCF4
t t 5.00 Year 5
26,234.69 ATCF5
After-Tax Net Cash Proceeds of Resale
The After-Tax Net Cash Proceeds of Resale (ATNCPR) is the after-tax reversion to
equity; generally, the estimated resale price of the property less commissions, outstanding
debt and any tax claim.
The After-Tax Net Cash Proceeds can be found using the HP 12C Platinum program
which follows.
20 Real Estate
This program uses declining balance depreciation to find the amount of depreciation from
purchase to sale. This amount is used to determine the excess depreciation (which is equal
to the amount of actual depreciation minus the amount of the straight line depreciation).
The Marginal Tax Rate (MTR) that the user inputs is applied to this excess depreciation.
The Capital Gains Tax Rate (CGTR) that the user inputs is applied to the capital gain
from purchase to sale less the expenses of sale (i.e. the NCPR or Net cash Proceeds of
Resale), plus the straight line depreciation.
The user may change to a different depreciation method by keying in the desired function
at line 026 (ALG: 029) in place of f#.
In addition the user may nullify the straight line depreciation by keying in a 0 at line 035
(ALG: 039) in place of fV. This means that all of the actual depreciation from
purchase to sale is then treated as "excess" or unrecaptured depreciation. This is
illustrated below in Example 2.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
g 001, 43 8 g 001, 43 8
?2 002, 44 2 ?2 002, 44 2
gA 003, 43 11 gA 003, 43 11
d 004, 33 d 004, 33
b 005, 25 ~ 005, 34
- 006, 30 - 006, 30
?0 007, 44 0 ~ 007, 34
~ 008, 34 b 008, 25
- 009, 30 - 009, 30
:7 010, 45 7 ?0 010, 44 0
b 011, 25 ~ 011, 34
?1 012, 44 1 § 012, 20
:P 013, 45 14 :7 013, 45 7
fB 014, 42 14 ³ 014, 36
P 015, 14 ?1 015, 44 1
M 016, 15 :P 016, 45 14
?+0 017,44 40 0 fB 017, 42 14
fCLEARG 018, 42 34 P 018, 14
:3 019, 45 3 M 019, 15
$ 020, 13 ?+0 020,44 40 0
:4 021, 45 4 fCLEARG 021, 42 34
n 022, 11 :3 022, 45 3
:5 023, 45 5 $ 023, 13
¼ 024, 12 :4 024, 45 4
:2 025, 45 2 n 025, 11
f# 026, 42 25 :5 026, 45 5
d 027, 33 ¼ 027, 12
Real Estate 21
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
:3 028, 45 3 :2 028, 45 2
~ 029, 34 f# 029, 42 25
- 030, 30 ~ 030, 34
:6 031, 45 6 :3 031, 45 3
b 032, 25 - 032, 30
?+1 033,44 40 1 ~ 033, 34
:2 034, 45 2 § 034, 20
fV 035, 42 23 :6 035, 45 6
:2 036, 45 2 ³ 036, 36
§ 037, 20 ?+1 037,44 40 1
:7 038, 45 7 :2 038, 45 2
:6 039, 45 6 fV 039, 42 23
- 040, 30 § 040, 20
b 041, 25 :2 041, 45 2
?+1 042,44 40 1 ³ 042, 36
:0 043, 45 0 :7 043, 45 7
:1 044, 45 1 - 044, 30
- 045, 30 :6 045, 45 6
g(000 046,43,33,000 § 046, 20
fs ~ 047, 34
+ 048, 40
:1 049, 45 1
§ 050, 20
1 051, 1
b 052, 25
- 053, 30
?1 054, 44 1
:0 055, 45 0
~ 056, 34
³ 057, 36
g(000 058,43,33,000
fs
REGISTERS
n: Used i: Used PV: Used PMT: Used
FV: Used R0: NCPR R
1: Tax paid R2: Desired yr.
R3: Dep. value R4: Dep. life R5: Factor R6: MTR
R7: CGTR R8-R.3: Unused
Program Instructions:
1. Key in the program and press fCLEARH.
22 Real Estate
2. Key in the loan values:
• Key in annual interest rate and press gC.
• Key in mortgage amount and press $.
• Key in monthly payment and press ÞP.
(If any of the values are unknown, they should be solved for and if one has
to be solved for then the correct payment mode needs to be set)
3. Key in depreciable value and press ?3.
4. Key in depreciable life in years and press ?4.
5. Key in accelerated depreciation factor for the declining balance method and press
?5.
6. Key in your Marginal Tax Rate as a percentage and press ?6.
7. Key in the Capital Gains Tax Rate as a percentage and press ?7.
8. Key in the purchase price and press \(³).
9. Key in the sale price and press \(³).
10. Key in the % commission charged on the sale and press \(³).
RPN: If a dollar value is desired instead of a commission rate, key in gÂ,
which does not affect the register values, at line 005 of the program.
ALG: If a dollar value is desired instead of a commission rate, key in gÂ,
which does not affect the register values, at line 008 of the program.
11. Key in the number of years after purchase and press t. The ATNCPR is
displayed.
12. To see the NCPR press :0 and to see the tax due press :1.
Example 1: An apartment complex, purchased for $900,000 ten years ago, is sold for
$1,750,000. The closing cost is 8% of the sale price, the income tax rate is 48% and the
capital gains tax rate is 19.2%.
A $700,000 loan for 20 years at 9.5% annual interest was used to purchase the complex.
When it was purchased the depreciable value was $750,000 with a useful life of 25 years.
Using 125% declining balance depreciation, what are the After-Tax Net Cash Proceeds in
year 10?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g gÂ
fCLEARH fCLEARH 0.00
700000$ 700000$ 700,000.00 Mortgage.
9.5gC 9.5gC 0.79 Monthly interest.
20gA 20gA 240.00 Number of
payments.
P PP -6,524.92 Monthly payment.
750000?3 750000?3 750,000.00 Depreciable value.
Real Estate 23
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
25?4 25?4 25.00 Depreciable life.
125?5 125?5 125.00 Factor.
48?6 48?6 48.00 Marginal Tax Rate.
19.2?7 19.2?7 19.20 Capital Gains Tax
Rate.
900000\ 900000³ 900,000.00 Purchase price.
1750000\ 1750000³ 1,750,000.00 Sale price.
8\ 8³ 8.00 Commission rate.
10t 10t 911,372.04
A
TNCPR.
:0 :0 1,105,746.74 NCPR.
:1 :1 194,374.70 Tax due on resale.
Example 2: Now, re-do the previous example assuming all depreciation is treated as
excess or unrecaptured depreciation, with MTR=25% and CGTR=15%.
First the fV in the program must be replaced with 0. This may be done as follows:
RPN: Press g(034 fs 0 fs.
ALG: Press g(038 fs 0 fs.
The data stored in registers R3-R5 need not be re-entered.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARG fCLEARG 0.00
700000$ 700000$ 700,000.00 Mortgage.
9.5gC 9.5gC 0.79 Monthly interest.
20gA 20gA 240.00 Number of
payments.
P PP -6,524.92 Monthly payment.
25?6 25?6 25.00 Marginal Tax Rate.
15?7 15?7 15.00 Capital Gains Tax
Rate.
900000\ 900000³ 900,000.00 Purchase price.
1750000\ 1750000³ 1,750,000.00 Sale price.
8\ 8³ 8.00 Commission rate.
10t 10t 924,009.92
A
TNCPR.
:0 :0 1,105,746.74 NCPR.
:1 :1 181,736.83 Tax due on resale.
24
Lending
Loan With a Constant Amount Paid Towards
Principal
This type of loan is structured such that the principal is repaid in equal installments with
the interest paid in addition. Therefore each periodic payment has a constant amount
applied toward the principle and a varying amount of interest.
Loan Reduction Schedule
If the constant periodic payment to principal, annual interest rate, and loan amount are
known, the total payment, interest portion of each payment, and remaining balance after
each successive payment may be calculated as follows:
RPN Mode:
1. Key in the constant periodic payment to principal and press ?0.
2. Key in periodic interest rate and press \\\.
3. Key in the loan amount. If you wish to skip to another time period, press \.
Then key in the number of payments to be skipped, and press :0§-.
4. Press ~b to obtain the interest portion of the payment.
5. Press :0+ to obtain the total payment.
6. Press O:0- to obtain the remaining balance of the loan.
7. Return to step 4 for each successive payment.
ALG Mode:
1. Key in the constant periodic payment to principal and press ?0.
2. Key in the loan amount and press ?1.
3. Key in periodic interest rate and press ?2.
If you wish to skip to another time period, key in the number of payments to be
skipped, and press §:0³?-1.
4. Press :1§:2b+ to obtain the interest portion of the payment.
5. Press :0?-1³ to obtain the total payment.
6. Press :1 to obtain the remaining balance of the loan.
7. Return to step 4 for each successive payment.
Lending 25
Example 1: A $60,000 land loan at 10% interest calls for equal semi-annual principal
payments over a 6-year maturity. What is the loan reduction schedule for the first year?
(Constant payment to principal is $5000 semi-annually). What is the fourth year's
schedule (skip 4 payments)?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
5000?0 5000?0
10\2z\ 60000?1
\\ 10z2³?2 5.00 Semi-annual interest rate.
60000~b :1§:2b+ 3,000.00 First payment's interest.
:0+ :0?-1³ 8,000.00 Total first payment.
O:0- :1 55,000.00 Remaining balance.
~b §:2b+ 2,750.00 Second payment's interest.
:0+ :0?-1³ 7,750.00 Total second payment.
O:0- :1 50,000.00 Remaining balance after
the first year.
4:0§- 4§:0³?-1
~b :1§:2b+ 1,500.00 Seventh payment's interest.
:0+ :0?-1³ 6,500.00 Total seventh payment.
O:0- :1 25,000.00 Remaining balance.
~b §:2b+ 1,250.00 Eighth payment's interest.
:0+ :0?-1³ 6,250.00 Total eighth payment.
O:0- :1 20,000.00 Remaining balance after
fourth year.
Add-On Interest Rate Converted to APR
An add-on interest rate determines what portion of the principal will be added on for
repayment of a loan. This sum is then divided by the number of months in a loan to
determine the monthly payment. For example, a 10% add-on rate for 36 months on $3000
means add one-tenth of $3000 for 3 years (300 x 3) - usually called the "finance charge" -
for a total of $3900. The monthly payment is $3900/36.
This keystroke procedure converts an add-on interest rate to a annual percentage rate
when the add-on rate and number of months are known.
26 Lending
RPN Mode:
1. Press g and press fCLEARG .
2. Key in the number of months in the loan and press n\:gA .
3. Key in the add-on rate and press §.
4. Key in the amount of the loan and press $*~b+.
5. Press ~zÞP.
6. Press ¼12§ to obtain the APR.
ALG Mode:
1. Press g and press fCLEARG .
2. Key in the number of months in the loan and press n³:gA§ .
3. Key in the add-on rate and press ³ .
4. Key in the amount of the loan and press $*+~bz .
5. Press ~³ÞP .
6. Press ¼§12³ to obtain the APR.
Example 1: Calculate the APR and monthly payment of a 12% $1000 add-on loan which
has a life of 18 months.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g gÂ
fCLEARG fCLEARG
18n\ 18n³
:gA12§ :gA§12³
1000$~b+ 1000$+~bz 1,180.00 Amount of loan.
~zÞP ~³ÞP -65.56 Monthly payment.
¼12§ ¼§12³ 21.64 Annual Percentage Rate.
APR Converted to Add-On Interest Rate
Given the number of months and annual percentage rate, this procedure calculates the
corresponding add-on interest rate.
1. Press g and press fCLEARG .
* Positive for cash received; negative for cash paid out.
Lending 27
2. Enter the following information:
a. Key in number of months of loan and press n .
b. Key in APR and press gC .
c. Key in 100 and press $P .
3. RPN: Press :$:nz+Þ12§ to obtain the add-on rate.
3. ALG: Press :$z:n+~§12³Þ to obtain the add-on rate.
Example 1: What is the equivalent add-on rate for an 18 month loan with an APR of
14%?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g gÂ
fCLEARG fCLEARG
18n14gC 18n14gC
100$P:$ 100$P:$
:nz+Þ z:n+~
12§ §12³Þ 7.63 Add-On Interest Rate.
Add-On Rate Loan with Credit Life
This HP 12C Platinum program calculates the monthly payment amount, credit life
amount (an optional insurance which cancels any remaining indebtedness at the death of
the borrower), total finance charge, and annual percentage rate (APR) for an add-on
interest rate (AIR) loan. The monthly payment is rounded (in normal manner) to the
nearest cent. If other rounding techniques are used, slightly different results may occur.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
g 001, 43 8 g 001, 43 8
1 002, 1 :0 002, 45 0
:0 003, 45 0 n 003, 11
1 004, 1 :gA 004,45,43 11
2 005, 2 b 005, 25
0 006, 0 ?4 006, 44 4
0 007, 0 § 007, 20
z 008, 10 :2 008, 45 2
?4 009, 44 4 ³ 009, 36
:2 010, 45 2 :4 010, 45 4
28 Lending
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
§ 011, 20 § 011, 20
- 012, 30 :1 012, 45 1
gF 013, 43 40 + 013, 40
:1 014, 45 1 1 014, 1
§ 015, 20 ³ 015, 36
:4 016, 45 4 y 016, 22
§ 017, 20 - 017, 30
- 018, 30 ~ 018, 34
:4 019, 45 4 § 019, 20
:1 020, 45 1 :0 020, 45 0
§ 021, 20 z 021, 10
1 022, 1 :3 022, 45 3
+ 023, 40 ³ 023, 36
~ 024, 34 y 024, 22
z 025, 10 fB 025, 42 14
:3 026, 45 3 Þ 026, 16
§ 027, 20 P 027, 14
:0 028, 45 0 t 028, 31
z 029, 10 Þ 029, 16
fB 030, 42 14 § 030, 20
Þ 031, 16 :0 031, 45 0
P 032, 14 § 032, 20
t 033, 31 :2 033, 45 2
:P 034, 45 14 § 034, 20
:0 035, 45 0 :4 035, 45 4
§ 036, 20 ³ 036, 36
Þ 037, 16 ?5 037, 44 5
$ 038, 13 § 038, 20
:$ 039, 45 13 Æ 039, 26
:2 040, 45 2 2 040, 2
b 041, 25 ³ 041, 36
:0 042, 45 0 gT 042, 43 24
§ 043, 20 gm 043, 43 35
1 044, 1 g(052 044,43,33,052
2 045, 2 1 045, 1
z 046, 10 b 046, 25
?5 047, 44 5 + 047, 40
Æ 048, 26 :5 048, 45 5
2 049, 2 ³ 049, 36
§ 050, 20 fB 050, 42 14
gT 051, 43 24 ?5 051, 44 5
gm 052, 43 35 :5 052, 45 5
g(061 053,43,33,061 t 053, 31
:5 054, 45 5 + 054, 40
Lending 29
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
. 055, 48 :3 055, 45 3
0 056, 0 $ 056, 13
1 057, 1 M 057, 15
+ 058, 40 Þ 058, 16
fB 059, 42 14 t 059, 31
?5 060, 44 5 0 060, 0
:5 061, 45 5 M 061, 15
t 062, 31 ¼ 062, 12
:$ 063, 45 13 :gC 063,45,43 12
~ 064, 34 g(000 064,43,33,000
- 065, 30 fs
:3 066, 45 3
- 067, 30
Þ 068, 16
t 069, 31
:5 070, 45 5
:3 071, 45 3
+ 072, 40
$ 073, 13
:0 074, 45 0
n 075, 11
¼ 076, 12
:gC 077,45,43 12
g(000 078,43,33,000
fs
REGISTERS
n: N i: i PV: Used PMT: PMT
FV: 0 R0: N R
1: AIR R
2: CL (%)
R3: Loan R4: N/1200 R5: Used R6-R9: Unused
Program Instructions:
1. Key in the program.
2. Press fCLEARG.
3. Key in the number of monthly payments in the loan and press ?0.
4. Key in the annual add-on interest rate as a percentage and press ?1.
5. Key in the credit life as a percentage and press ?2.
6. Key in the loan amount and press ?3.
7. Press t to find the monthly payment amount.
8. Press t to obtain the amount of credit life.
30 Lending
9. Press t to calculate the total finance charge.
10. Press t to calculate the annual percentage rate.
11. For a new loan return to step 3.
Example 1: You wish to quote a loan on a $3100 balance, payable over 36 months at an
add-on rate of 6.75%. Credit life (CL) is 1%. What are the monthly payment amount,
credit life amount, total finance charge, and APR?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARG fCLEARG
36?0 36?0 36.00 Months.
6.75?1 6.75?1 6.75 Add-on interest rate.
1?2 1?2 1.00 Credit life (%).
3100?3 3100?3 3100.00 Loan.
t t -107.42 Monthly payment.
t t 116.02 Credit life.
t t -651.10 Total finance charge.
t t 12.39 APR.
Interest Rebate - Rule of 78's
This procedure finds the unearned interest rebate, as well as the remaining principal
balance due for a prepaid consumer loan using the Rule of 78's. The known values are the
current installment number, the total number of installments for which the loan was
written, and the total finance charge (amount of interest). The information is entered as
follows:
RPN Mode:
1. Key in number of months in the loan and press ?1.
2. Key in payment number when prepayment occurs and press -?2 1+.
3. Key in total finance charge and press §:1\§:1+z:2§ to
obtain the unearned interest (rebate).
4. Key in periodic payment amount and press :2§~- to obtain the amount of
principal outstanding.
ALG Mode:
1. Key in number of months in the loan and press ?1-.
2. Key in payment number when prepayment occurs and press³?2+1§.
3. Key in total finance charge and press ³:1g’+:1z~~§:2
³ to obtain the unearned interest (rebate).
4. Key in periodic payment amount and press §:2-~³ to obtain the amount
of principal outstanding.
Lending 31
Example 1: A 30 month $1000 loan having a finance charge of $180, is being repaid at
$39.33 per month. What is the rebate and balance due after the 25th regular payment?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
30?1 30?1
25-?2 -25³?2
1+180§ +1§180³
:1\ :1g’+:1
§:1+ z~~§
z:2§ :2³ 5.81 Rebate.
39.33:2§ 39.33§:2
~- -~³ 190.84 Outstanding principal.
The following HP 12C Platinum program can be used to evaluate the previous example.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
?0 001, 44 0 ?0 001, 44 0
d 002, 33 d 002, 33
?2 003, 44 2 ~ 003, 34
d 004, 33 ?1 004, 44 1
?1 005, 44 1 ?2 005, 44 2
:2 006, 45 2 ~ 006, 34
- 007, 30 ?-2 007,44 30 2
?2 008, 44 2 :1 008, 45 1
1 009, 1 g’ 009, 43 20
+ 010, 40 + 010, 40
:0 011, 45 0 :1 011, 45 1
§ 012, 20 ³ 012, 36
:1 013, 45 1 :2 013, 45 2
\ 014, 36 g’ 014, 43 20
§ 015, 20 + 015, 40
:1 016, 45 1 :2 016, 45 2
+ 017, 40 z 017, 10
z 018, 10 ~ 018, 34
:2 019, 45 2 § 019, 20
§ 020, 20 :0 020, 45 0
t 021, 31 ³ 021, 36
:2 022, 45 2 t 022, 31
§ 023, 20 § 023, 20
~ 024, 34 :2 024, 45 2
- 025, 30 - 025, 30
32 Lending
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
g(000 026,43,33,000 ~ 026, 34
fs ³ 027, 36
g(000 028,43,33,000
fs
REGISTERS
N: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: Fin. charge R1: # months R2: Payment #
R3-R.6: Unused
Program Instructions:
1. Key in the program.
2. Key in the number of months in the loan and press \(³).
3. Key in the payment number when prepayment occurs and press \(³).
4. Key in the total finance charge and press t to obtain the unearned interest
(rebate).
5. Key in the periodic payment amount and press t to find the amount of principal
outstanding.
6. For a new case return to step 2.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
30\ 30³
25\ 25³
180t 180t 5.81 Rebate.
39.33t 39.33t 190.84 Outstanding principal.
Graduated Payment Mortgages
The Graduated Payment Mortgage is designed to meet the needs of young home buyers
who currently cannot afford high mortgage payments, but who have the potential of
increasing earning in the years to come.
Under the Graduated Payment Mortgage plan, the payments increase by a fixed
percentage at the end of each year for a specified number of years. Thereafter, the
payment amount remains constant for remaining life of the mortgage.
The result is that the borrower pays a reduced payment (a payment which is less than a
traditional mortgage payment) in the early years, and in the later years makes larger
payments than he would with a traditional loan. Over the entire term of the mortgage, the
borrower would pay more than he would with conventional financing.
Lending 33
Given the term of the mortgage (in years), the annual percentage rate, the loan amount,
the percentage that the payments increase, and the number of years that the payments
increase, the following HP 12C Platinum program determines the monthly payments and
remaining balance for each year until the level payment is reached.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
g 001, 43 8 g 001, 43 8
?2 002, 44 2 ?2 002, 44 2
~ 003, 34 ~ 003, 34
1 004, 1 b 004, 25
b 005, 25 + 005, 40
1 006, 1 1 006, 1
+ 007, 40 ³ 007, 36
?0 008, 44 0 y 008, 22
:n 009, 45 11 ?0 009, 44 0
:2 010, 45 2 :n 010, 45 11
- 011, 30 - 011, 30
gA 012, 43 11 :2 012, 45 2
:¼ 013, 45 12 ³ 013, 36
gC 014, 43 12 gA 014, 43 11
:$ 015, 45 13 :¼ 015, 45 12
?3 016, 44 3 gC 016, 43 12
1 017, 1 :$ 017, 45 13
Þ 018, 16 ?3 018, 44 3
P 019, 14 ?4 019, 44 4
$ 020, 13 1 020, 1
Þ 021, 16 P 021, 14
M 022, 15 $ 022, 13
1 023, 1 Þ 023, 16
gA 024, 43 11 M 024, 15
:P 025, 45 14 1 025, 1
:0 026, 45 0 gA 026, 43 11
z 027, 10 :P 027, 45 14
P 028, 14 § 028, 20
$ 029, 13 :0 029, 45 0
Þ 030, 16 P 030, 14
M 031, 15 $ 031, 13
1 032, 1 Þ 032, 16
?+1 033,44 40 1 M 033, 15
:1 034, 45 1 1 034, 1
:2 035, 45 2 ?+1 035,44 40 1
- 036, 30 :1 036, 45 1
34 Lending
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
gm 037, 43 35 - 037, 30
g(040 038,43,33,040 :2 038, 45 2
g(025 039,43,33,025 ³ 039, 36
:3 040, 45 3 gm 040, 43 35
:$ 041, 45 13 g(043 041,43,33,043
z 042, 10 g(027 042,43,33,027
?4 043, 44 4 :$ 043, 45 13
:3 044, 45 3 ?z4 044,44 10 4
$ 045, 13 :3 045, 45 3
1 046, 1 $ 046, 13
?3 047, 44 3 1 047, 1
:3 048, 45 3 ?3 048, 44 3
t 049, 31 :3 049, 45 3
:4 050, 45 4 t 050, 31
1 051, 1 :0 051, 45 0
:0 052, 45 0 q 052, 21
:1 053, 45 1 :1 053, 45 1
q 054, 21 § 054, 20
z 055, 10 :4 055, 45 4
§ 056, 20 ³ 056, 36
Þ 057, 16 fB 057, 42 14
fB 058, 42 14 t 058, 31
P 059, 14 P 059, 14
t 060, 31 M 060, 15
M 061, 15 fB 061, 42 14
M 062, 15 t 062, 31
fB 063, 42 14 Þ 063, 16
t 064, 31 $ 064, 13
Þ 065, 16 1 065, 1
$ 066, 13 ?+3 066,44 40 3
1 067, 1 ?-1 067,44 30 1
?+3 068,44 40 3 :1 068, 45 1
?-1 069,44 30 1 gm 069, 43 35
:1 070, 45 1 g(072 070,43,33,072
gm 071, 43 35 g(049 071,43,33,049
g(074 072,43,33,074 :4 072, 45 4
g(048 073,43,33,048 t 073, 31
:4 074, 45 4 g(073 074,43,33,073
Þ 075, 16 fs
t 076, 31
g(076 077,43,33,076
fs
Lending 35
REGISTERS
n: Used i: i/12 PV: Used PMT: Used
FV: Used R0: Used R1: Used R2: Used
R3: Used R4: Level Pmt. R5-R9: Unused
Program Instructions:
1. Key in the program.
2. Press fCLEARH.
3. Key in the term of the loan and press n.
4. Key in the annual interest rate and press ¼.
5. Key in the total loan amount and press $.
6. Key in the rate of graduation (as a percent) and press \(³).
7. Key in the number of years for which the loan graduates and press t. The
following information will be displayed for each year until a level payment is
reached.
a. The current year.
Then press t to continue.
b. The monthly payment for the current year.
Then press t to continue.
c. The remaining balance to be paid on the loan at the end of the current year.
Then press t to return to step a. unless the level payment is reached.
If the level payment has been reached, the program will stop, displaying
the monthly payment over the remaining term of the loan.
8. For a new case press g(000 and return to step 2.
Example: A young couple recently purchased a new house with a Graduated Payment
Mortgage. The loan is for $50,000 over a period of 30 years at an annual interest rate of
12.5%. The monthly payments will be graduating at an annual rate of 5% for the first 5
years and then will be level for the remaining 25 years. What are the monthly payment
amount for the first 6 years?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH 0.00
30n 30n 30.00 Term
12.5¼ 12.5¼ 12.50 Annual interest rate
50000$ 50000$ 50,000.00 Loan amount
5\ 5³ 5.00 Rate of graduation
5t 5t 1.00 Year 1
t t -448.88 1st year monthly payment.
t t -50,914.67 Remaining balance after 1st
year.
t t 2.00 Year 2
t t -471.33 2nd year monthly payment.
t t -51,665.07 Remaining balance after 2nd
year.
36 Lending
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
t t 3.00 Year 3
t t -494.89 3rd year monthly payment.
t t -52,215.34 Remaining balance after 3rd
year.
t t 4.00 Year 4
t t -519.64 4th year monthly payment.
t t -52,523.86 Remaining balance after 4th
year.
t t 5.00 Year 5
t t -545.62 5th year monthly payment.
t t -52,542.97 Remaining balance after 5th
year.
t t -572.90 Monthly payment for
remainder of term.
Variable Rate Mortgages
As its name suggests, a variable rate mortgage is a mortgage loan which provides for
adjustment of its interest rate as market interest rates change. As a result, the current
interest rate on a variable rate mortgage may differ from its origination rate (i.e., the rate
when the loan was made). This is the difference between a variable rate mortgage and the
standard fixed payment mortgage, where the interest rate and the monthly payment are
constant throughout the term.
Under the agreement of the variable rate mortgage, the mortgage is examined periodically
to determine any rate adjustments. The rate adjustment may be implemented in two ways:
1. Adjusting the monthly payment.
2. Modifying the term of the mortgage.
The period and limits to interest rate increases vary from state to state.
Each periodic adjustment may be calculated by using the HP 12C Platinum with the
following keystroke procedure. The original terms of the mortgage are assumed to be
known.
1. Press g and press fCLEARG.
2. Key in the remaining balance of the loan and press $.
The remaining balance is the difference between the loan amount and the total
principal from the payments which have been made.
To calculate the remaining balance, do the following:
a. Key in the previous remaining balance. If this is the first mortgage adjustment,
this value is the original amount of the loan. Press $.
b. Key in the annual interest rate before the adjustment (as a percentage) and press
gC.
Lending 37
c. Key in the number of years since the last adjustment. If this is the first mortgage
adjustment, then key in the number of years since the origination of the mortgage.
Press gA.
d.
Key in the monthly payment over this period and press ÞP.
e.
Press M to find the remaining balance, then press fCLEARGÞ$.
3. Key in the adjusted annual interest rate (as a percentage) and press gC.
To calculate the new monthly payment:
a.
Key in the remaining life of the mortgage (years) and press gA.
b.
RPN: Press P to find the new monthly payment.
b.
ALG: Press PP to find the new monthly payment.
To calculate the revised remaining term of the mortgage:
a.
Key in the present monthly payment and press P.
b.
RPN: Press n12z to find the remaining term of the mortgage in years.
b.
ALG: Press nz12³ to find the remaining term of the mortgage in years.
Example: A homeowner purchased his house 3 years ago with a $50,000 variable rate
mortgage. With a 30 year term, his current monthly payment is $495.15. When the
interest rate is adjusted from 11.5% to 11.75%, what will the monthly payment be? If the
monthly payment remained unchanged, find the revised remaining term on the mortgage.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g gÂ
fCLEARG fCLEARG
50000$ 50000$ 50,000.00 Original amount of loan.
11.5gC 11.5gC 0.96 Original monthly interest rate.
3gA 3gA 36.00 Period.
495.15ÞP 495.15ÞP -495.15 Previous monthly payment.
M M -49,316.74
fCLEARG fCLEARG
Þ$ Þ$ 49,316.74 Remaining balance.
11.75gC 11.75gC 0.98 Adjusted monthly interest.
30\3- 30-3³ 27.00 Remaining life of mortgage.
gA gA 324.00
P PP -504.35 New monthly payment.
495.15ÞP 495.15ÞP -495.15 Previous monthly payment.
n12z nz12³ 31.67 New remaining term (years).
38 Lending
Skipped Payments
Sometimes a loan (or lease) may be negotiated in which a specific set of monthly
payments are going to be skipped each year. Seasonally is usually the reason for such an
agreement. For example, because of heavy rainfall, a bulldozer cannot be operated in
Oregon during December, January, and February, and the lessee wishes to make payments
only when his machinery is being used. He will make nine payments per year, but the
interest will continue to accumulate over the months in which a payment is not made.
To find the monthly payment amount necessary to amortize the loan in the specified
amount of time, information is entered as follows:
1. Press g and press fCLEARG.
2. Key in the number of the last payment period before payments close the first time
and press n.
3. Key in the annual interest rate as a percentage and press gC1PM.
RPN Mode:
4. Press Þ$12:n-n0PM?0:n.
5. Key in the number of payments which are skipped and press -
n1P0$M?+0.
6. Press 0P12n100$M:$+ÞfCLEARG¼
7. Key in the total number of years in the loan and press n.
8. Key in the loan amount and press $P:0z to obtain the monthly payment
amount when the payment is made at the end of the month.
9. Press ÞM0P1n.
10. Key in the annual interest rate as a percent and press gC$ to find the
monthly payment amount when the payment is made at the beginning of the month.
ALG Mode:
4. Press Þ$12-:nn0PM?0:n-.
5. Key in the number of payments which are skipped and press
n1P0$M?+0.
6. Press 0P12n100$M+:$³ÞfCLEARG¼
7. Key in the total number of years in the loan and press n.
8. Key in the loan amount and press $Pz:0³ to obtain the monthly
payment amount when the payment is made at the end of the month.
9. Press ÞM0P1n.
10. Key in the annual interest rate as a percent and press gC$$ to find the
monthly payment amount when the payment is made at the beginning of the month.
Lending 39
Example: A bulldozer worth $100,000 is being purchased in September. The first
payment is due one month later, and payments will continue over a period of 5 years. Due
to the weather, the machinery will not be used during the winter months, and the
purchaser does not wish to make payments during January, February, and March (months
4 thru 6). If the current interest rate is 14%, what is the monthly payment necessary to
amortize the loan?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g gÂ
fCLEARG fCLEARG
3n 3n 3.00 Number of payments made
before a group of payments is
skipped.
14gC 14gC 1.17 Monthly interest rate.
1PMÞ$ 1PMÞ$
12:n-n 12-:nn
0PM?0 0PM?0 -3.37 FV of 3 monthly unit PMTs.
:n3-n :n-3n
1P0$M 1P0$M
?+0 ?+0 -6.18 FV of 6 monthly unit PMTs.
0P12n 0P12n
100$M 100$M
:$+Þ +:$³Þ
fCLEARG¼ fCLEARG¼ 14.93 Effective annual interest rate
5n100000$ 5n100000$
P:0z Pz:0³ 3,119.89 Monthly payment in arrears.
40
Savings
Initial Deposit with Periodic Deposits
Given an initial deposit into a savings account, and a series of periodic deposits coincident
with the compounding period, the future value (or accumulated amount) may be
calculated as follows:
1. Press g and press fCLEARG.
2. Key in the initial investment and press Þ$.
3. Key in the number of additional periodic deposits and press n.
4. Key in the periodic interest rate and press ¼.
5. Key in the periodic deposit and press ÞP.
6. Press M to determine the value of the account at the end of the time period.
Example: You have just opened a savings account with a $200 deposit. If you deposit
$50 a month, and the account earns 5 ¼ % compounded monthly, how much will you
have in 3 years?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g gÂ
fCLEARG fCLEARG
200Þ$ 200Þ$
3gA 3gA
5.25gC 5.25gC
50ÞPM 50ÞPM 2,178.94 Value of the account.
Note: If the periodic deposits do not coincide with the compounding periods, the account
must be evaluated in another manner. First, find the future value of the initial deposits and
store it. Then use the procedure for compounding periods different from payment periods
to calculate the future value of the periodic deposits. Recall the future value of the initial
deposit and add to obtain the value of the account.
Savings 41
Number of Periods to Deplete a Savings
Account or to Reach a Specified Balance
Given the current value of a savings account, the periodic interest rate, the amount of the
periodic withdrawal, and a specified balance, this procedure determines the number of
periods to reach that balance (the balance is zero if the account is depleted).
1. Press g and press fCLEARG.
2. Key in the value of the savings account and press Þ$.
3. Key in the periodic interest rate and press ¼.
4. Key in the amount of the periodic withdrawal and press P.
5. Key in the amount remaining in the account and press M.
This step may be omitted if the account is depleted (FV=0).
6. Press n to determine the number of periods to reach the desired balance.
Example: Your savings account presently contains $18,000 and earns 5 ½% compounded
monthly. You wish to withdraw $300 a month until the account is depleted. How long
will this take? If you wish to reduce the account to $5000, how many withdrawals can you
make?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g gÂ
fCLEARG fCLEARG
18000Þ$ 18000Þ$
5.5gC 5.5gC
300Pn 300Pn 71.00 Months to deplete account.
5000Mn 5000Mn 53.00 Months to reduce the account to
$5000.
42 Savings
Periodic Deposits and Withdrawals
This section is presented as a guideline for evaluating a savings plan when deposits and
withdrawals occur at irregular intervals. One problem is given, and a step by step method
for setting up and solving the problem is presented:
Example: You are presently depositing $50 and the end of each month into a local
savings and loan, earning 5 ½% compounded monthly. Your current balance is $1023.25.
How much will you have accumulated in 5 months?
The cash flow diagram looks like this:
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g gÂ
fCLEARG fCLEARG
50ÞP 50ÞP
5.5gC 5.5gC
1023.25Þ$ 1023.25Þ$
5nM 5nM 1,299.22 Amount in account.
Now suppose that at the beginning of the 6th month you withdrew $80.
What is the new balance?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
80- -80³ 1,219.22 New balance.
PV
= - 1023.25
FV
= ?
-50-50-50- 50 -50
1 3 4 52
Savings 43
You increase your monthly deposit to $65. How much will you have in 3 months?
The cash flow diagram looks like this:
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
Þ$ Þ$
65ÞP 65ÞP
3nM 3nM 1,431.95 Account balance.
Suppose that for 2 months you decide not to make a periodic deposit. What is the balance
in the account?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
Þ$2n Þ$2n
0PM 0PM 1,445.11 Account balance.
PV
= - 1219.22
FV
= ?
-65-65-65
1 3 2
1 2
FV
= ?
PV
= - 1431.95
44 Savings
This type of procedure may be continued for any length of time, and may be modified to
meet the user's particular needs.
Savings Account Compounded Daily
This HP 12C Platinum program determines the value of a savings account when interest is
compounded daily, based on a 365 day year. The user is able to calculate the total amount
remaining in the account after a series of transactions on specified dates.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
Þ 001, 16 Þ 001, 16
$ 002, 13 $ 002, 13
d 003, 33 d 003, 33
3 004, 3 z 004, 10
6 005, 6 3 005, 3
5 006, 5 6 006, 6
z 007, 10 5 007, 5
¼ 008, 12 ¼ 008, 12
d 009, 33 d 009, 33
?0 010, 44 0 ?0 010, 44 0
:$ 011, 45 13 :$ 011, 45 13
Þ 012, 16 Þ 012, 16
t 013, 31 t 013, 31
?2 014, 44 2 ?2 014, 44 2
d 015, 33 d 015, 33
?1 016, 44 1 ?1 016, 44 1
:0 017, 45 0 :0 017, 45 0
:1 018, 45 1 :1 018, 45 1
gÒ 019, 43 26 gÒ 019, 43 26
n 020, 11 n 020, 11
M 021, 15 M 021, 15
fB 022, 42 14 fB 022, 42 14
M 023, 15 M 023, 15
\ 024, 36 + 024, 40
:$ 025, 45 13 :$ 025, 45 13
+ 026, 40 ³ 026, 36
?+3 027,44 40 3 ?+3 027,44 40 3
:M 028, 45 15 :M 028, 45 15
:2 029, 45 2 Þ 029, 16
+ 030, 40 - 030, 30
Þ 031, 16 :2 031, 45 2
Savings 45
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
$ 032, 13 $ 032, 13
:1 033, 45 1 :1 033, 45 1
?0 034, 44 0 ?0 034, 44 0
:$ 035, 45 13 :$ 035, 45 13
Þ 036, 16 Þ 036, 16
g(013 037,43,33,013 g(013 037,43,33,013
fs fs
REGISTERS
N: ∆days i: i/365 PV: Used PMT: 0
FV: Used R0: Initial date R1: Next date R2: $ amount
R3: Interest R4-R.4: Unused
Program Instructions:
1. Key in the program.
2. Press fCLEARH and press gÕ.
3. Key in the date (MM.DDYYYY) of the first transaction and press \(³).
4. Key in the annual nominal interest rate as a percentage and press \(³).
5. Key in the amount of the initial deposit and press t.
6. Key in the date of the next transaction and press \(³).
7. Key in the amount of the transaction (positive for money deposited, negative for cash
withdrawn) and press t to determine the amount in the account.
8. Repeat steps 6 and 7 for subsequent transactions.
9. To see the total interest to date, press :3.
10. For a new case press f(000 and go to step 2.
Example: Compute the amount remaining in this 5.25% account after the
following transactions:
1. January 19, 2003 deposit $125.00
2. February 24, 2003 deposit $60.00
3. March 16, 2003 deposit $70.00
4. April 6, 2003 withdraw $50.00
5. June 1, 2003 deposit $175.00
6 July 6, 2003 withdraw $100.00
46 Savings
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH
gÕ gÕ
1.192003\ 1.192003³
5.25\ 5.25³
125t 125t 125.00 Initial Deposit.
2.242003\ 2.242003³
60t 60t 185.65 Balance in account,
February 24, 2003.
3.162003\ 3.162003³
70t 70t 256.18 Balance in account,
March 16, 2003.
4.062003\ 4.062003³
50Þt 50Þt 206.95 Balance in account,
April 6, 2003.
6.012003\ 6.012003³
175t 175t 383.62 Balance in account,
June 1, 2003.
7.062003\ 7.062003³
100Þt 100Þt 285.56 Balance in account,
July 6, 2003.
:3 :3 5.56 Total interest.
Compounding Periods Different From
Payment Periods
In financial calculations involving a series of payments equally spaced in time with
periodic compounding, both periods of time are normally equal and coincident. This
assumption is preprogrammed into the HP 12C Platinum.
In savings plans however, money may become available for deposit or investment at a
frequency different from the compounding frequencies offered. The HP 12C Platinum can
easily be used in these calculations. However, because of the assumptions mentioned the
periodic interest rate must be adjusted to correspond to an equivalent rate for the payment
period.
Payments deposited for a partial compounding period will accrue simple interest for the
remainder of the compounding period. This is often the case, but may not be true for all
institutions.
These procedures present solutions for future value, payment amount, and number of
payments. In addition, it should be noted that only annuity due (payments at the beginning
of payment period) calculations are shown since this is the most common in savings plan
calculations.
Savings 47
To calculate the equivalent payment period interest rate, information is entered as follows:
1. Press g× and press fCLEARG.
RPN Mode:
2. Key in the annual interest rate (as a percent) and press \.
3. Key in the number of compounding periods per year and press nz¼.
ALG Mode:
2. Key in the number of compounding periods per year and press n.
3. Key in the annual interest rate (as a percent) and press z:n¼.
4. Key in 1 and press $M.
5. Key in the number of payments (deposits) per year and press
n¼fCLEARG¼.
The interest rate which corresponds to the payment period is now in register "i" and you
are ready to proceed.
Example 1: Solving for future value.
Starting today you make monthly deposits of $25 into an account paying 5% compounded
daily (365-day basis). At the end of 7 years, how much will you receive from the account?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g× g×
fCLEARG fCLEARG
5\ 365n
365nz¼ 5z:n¼
1$M 1$M
12n¼ 12n¼
fCLEARG¼ fCLEARG¼ 0.42 Equivalent periodic interest
rate.
7gA 7gA
25ÞP 25ÞP
M M 2,519.61 Future value.
48 Savings
Example 2: Solving for payment amount.
For 8 years you wish to make weekly deposits in a savings account paying 5.5%
compounded quarterly. What amount must you deposit each week to accumulate $6000.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g× g×
fCLEARG fCLEARG
5.5\ 4n
4nz¼ 5.5z:n¼
1$M 1$M
52n¼ 52n¼
fCLEARG¼ fCLEARG¼ 0.11 Equivalent periodic interest
rate.
8\52§n 8§52n
6000MP 6000MP -11.49 Periodic payment.
Example 3: Solving for number of payment periods.
You can make weekly deposits of $10 in to an account paying 5.25% compounded daily
(365-day basis). How long will it take you to accumulate $1000?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g× g×
fCLEARG fCLEARG
5.25\ 365n
365nz¼ 5.25z:n¼
1$M 1$M
52n¼ 52n¼
fCLEARG¼ fCLEARG¼ 0.10 Equivalent periodic interest
rate.
10ÞP 10ÞP
1000Mn 1000Mn 96.00 Weeks.
49
Investment Analysis
Lease vs. Purchase
An investment decision frequently encountered is the decision to lease or purchase capital
equipment or buildings. Although a thorough evaluation of a complex acquisition usually
requires the services of a qualified accountant, it is possible to simplify a number of the
assumptions to produce a first approximation.
The following HP 12C Platinum program assumes that the purchase is financed with a
loan and that the loan is made for the term of the lease. The tax advantages of interest
paid, depreciation, and the investment credit which accrues from ownership are compared
to the tax advantage of treating the lease payment as an expense. The resulting cash flows
are discounted to the present at the firm's after-tax cost of capital.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
- 001, 30 - 001, 30
1 002, 1 ~ 002, 34
?+0 003,44 40 0 ³ 003, 36
:3 004, 45 3 ?8 004, 44 8
- 005, 30 1 005, 1
§ 006, 20 ?+0 006,44 40 0
?8 007, 44 8 f! 007, 42 11
1 008, 1 ?1 008, 44 1
f! 009, 42 11 :$ 009, 45 13
?1 010, 44 1 ?9 010, 44 9
:$ 011, 45 13 :¼ 011, 45 12
?9 012, 44 9 ?.2 012,44 48 2
:P 013, 45 14 :5 013, 45 5
?.0 014,44 48 0 $ 014, 13
:n 015, 45 11 :6 015, 45 6
?.1 016,44 48 1 n 016, 11
:¼ 017, 45 12 :7 017, 45 7
?.2 018,44 48 2 ¼ 018, 12
:5 019, 45 5 :0 019, 45 0
$ 020, 13 fÝ 020, 42 24
:6 021, 45 6 ?+1 021,44 40 1
n 022, 11 :9 022, 45 9
50 Investment Analysis
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
:7 023, 45 7 $ 023, 13
¼ 024, 12 :.2 024,45 48 2
:0 025, 45 0 ¼ 025, 12
fÝ 026, 42 24 :1 026, 45 1
?+1 027,44 40 1 - 027, 30
:9 028, 45 9 :8 028, 45 8
$ 029, 13 § 029, 20
:.0 030,45 48 0 :3 030, 45 3
P 031, 14 + 031, 40
:.1 032,45 48 1 :8 032, 45 8
n 033, 11 - 033, 30
:.2 034,45 48 2 :P 034, 45 14
¼ 035, 12 ³ 035, 36
:1 036, 45 1 :4 036, 45 4
:3 037, 45 3 q 037, 21
§ 038, 20 :0 038, 45 0
:P 039, 45 14 z 039, 10
- 040, 30 ~ 040, 34
:8 041, 45 8 ~ 041, 34
- 042, 30 ³ 042, 36
:4 043, 45 4 ?+2 043,44 40 2
:0 044, 45 0 g(000 044,43,33,000
q 045, 21 fs
z 046, 10
?+2 047,44 40 2
g(000 048,43,33,000
fs
REGISTERS
n: Used i: Used PV: Used PMT: Used
FV: 0 R0: Used R1: Used R2: Purch. Adv.
R3: Tax R4: Discount R5: Dep. Value R6: Dep. life
R7: Factor (DB) R8: Used R9: Used R.0: Used
R.1: Used R.2: Used R.3: Unused
Program Instructions:
1. Key in the program.
RPN: - Select the depreciation function and key in at line 26.
ALG: - Select the depreciation function and key in at line 20.
2. Press g and press fCLEARH.
3. Input the following information for the purchase of the loan:
- Key in the number of years for amortization and press n.
Investment Analysis 51
- Key in the annual interest rate and press ¼.
- Key in the loan amount (purchase price) and press Þ$.
- Press P to find the annual payment.
4. Key in the marginal effective tax rate* and press ?3.
5. RPN: Key in the discount rate or cost of capital* and press \1+?4.
5. ALG: Key in the discount rate or cost of capital* and press +1³?4.
6. Key in the depreciable value and press ?5.
7. Key in the depreciable life and press ?6.
8. For declining balance depreciation, key in the depreciation factor (as a percentage)
and press ?7.
9. RPN: Key in the total first lease payment (including any advance payments) and
press \1:3-§?2.
9. ALG: Key in the total first lease payment (including any advance payments) and
press ³1-:3§~³?2.
10. Key in the first year's maintenance expense that would be anticipated if the asset was
owned and press \(³) . If the lease contract does not include maintenance, then
it is not a factor in the lease vs. purchase decision and 0 expense should be used.
11. Key in the next lease payment and press t. During any year in which a lease
payment does not occur (e.g. the last several payments of an advance payment
contract) use 0 for the payment.
12. Repeat steps 10 and 11 for all maintenance expenses and lease payments over the
term of the analysis.
Optional - If the investment tax credit is taken, key in the amount of the credit after
finishing steps 10 and 11 for the year in which the credit is taken and press
g(043 (ALG:036) t . Continue steps 10 and 11 for the remainder of the
term.
13. RPN: After all the lease payments and expenses have been entered (steps 10 and 11),
key in the lease buy back option and press \1:3-§g(043t. If no
buy back option exists, use the estimated salvage value of the purchased equipment at
the end of the term.
13. ALG: After all the lease payments and expenses have been entered (steps 10 and 11),
key in the lease buy back option and press ³1-
:3§~³g(036t. If no buy back option exists, use the estimated
salvage value of the purchased equipment at the end of the term.
14. To find the net advantage of owning press :2. A negative value represents a net
lease advantage.
Example: Home Style Bagel Company is evaluating the acquisition of a mixer which can
be leased for $1700 a year with the first and last payments in advance and a $750 buy
back option at the end of 10 years (maintenance is included).
The same equipment could be purchased for $10,000 with a 12% loan amortized over 10
years. Ownership maintenance is estimated to be 2% of the purchase price per year for the
first for years. A major overhaul is predicted for the 5th year at a cost of $1500.
Subsequent yearly maintenance of 3% is estimated for the remainder of the 10 year term.
The company would use sum of the years digits depreciation on a 10 year life with $1500
* Key in as a decimal (e.g., 5% as .05).
52 Investment Analysis
salvage value. An accountant informs management to take the 10% capital investment tax
credit at the end of the second year and to figure the cash flows at a 48% tax rate. The
after tax cost of capital (discounting rate) is 5 percent.
Because lease payments are made in advance and standard loan payments are made in
arrears the following cash flow schedule is appropriate for a lease with the last payment in
advance.
Year Maintenance Lease Payment Tax Credit Buy Back
0 1700+1700
1 200 1700
2 200 1700 1000
3 200 1700
4 200 1700
5 1500 1700
6 300 1700
7 300 1700
8 300 1700
9 300 0
10 300 0 750
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g gÂ
fCLEARH fCLEARH 0.00
10n12¼ 10n12¼
10000Þ$ 10000Þ$ -10,000.00 Always use negative loan
amount.
P P 1,769.84 Purchase payment.
.48?3 .48?3 0.48 Marginal tax rate.
.05\1+?4 .05+1³?4 1.05 Discounting factor.
10000\ 10000-
1500-?5 1500³?5 8,500.00 Depreciable value.
10?6 10?6 10.00 Depreciable life.
1700\+ 1700+³ 3,400.00 1st lease payment.
1:3-§?2 1-:3§~
³?2
1,768.00 After-tax expense.
200\ 200³
1700t 1700t 312.36 Present value of 1st year's
net purchase.
200\ 200³
1700t 1700t 200.43 2nd year's advantage.
1000g(043 1000g(036 1,000.00 Tax credit.
t t 907.03 Present value of tax credit.
200\ 200³
1700t 1700t 95.05 3rd year.
200\ 200³
1700t 1700t -4.38 4th year.
Investment Analysis 53
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
1500\ 1500³
1700t 1700t -628.09 5th year.
300\ 300³
1700t 1700t -226.44 6th year.
300\ 300³
1700t 1700t -309.48 7th year.
300\ 300³
1700t 1700t -388.81 8th year.
300\0t 300³0t -1,034.72 9th year.
300\0t 300³0t -1,080.88 10th year.
750\ 750³ 750.00 Buy back.
1:3-§ 1-:3§~³ 390.00 After tax buy back
expense.
g(043t g(036t 239.43 Present value.
:2 :2 -150.49 Net lease advantage.
Break-Even Analysis
Break-even analysis is basically a technique for analyzing the relationships among fixed
costs, variable costs, and income. Until the break-even point is reached at the intersection
of the total sales revenue and total cost lines, the producer operates at a loss. After the
break-even point each unit produced and sold makes a profit. Break-even analysis may be
represented as follows.
Fixed Costs
Profit
Break-even Point
Variable
Costs
54 Investment Analysis
The variables are: fixed costs (F), Sales price per unit (P), variable cost per unit (V),
number of units sold (U), and gross profit (GP). One can readily evaluate GP, U or P
given the four other variables. To calculate the break-even volume, simply let the gross
profit equal zero and calculate the number of units sold (U).
To calculate the break-even volume:
RPN Mode:
1. Key in the fixed costs and press \.
2. Key in the unit price and press \.
3. Key in the variable cost per unit and press -.
4. Press z to calculate the break-even volume.
ALG Mode:
1. Key in the fixed costs and press ³.
2. Key in the unit price and press -.
3. Key in the variable cost per unit and press z.
4. Press ~~³ to calculate the break-even volume.
To calculate the gross profit at a given volume:
RPN Mode:
1. Key in the unit price and press \.
2. Key in the variable cost per unit and press -.
3. Key in the number of units sold and press §.
4. Key in the fixed cost and press - to calculate the gross profit.
ALG Mode:
1. Key in the unit price and press -.
2. Key in the variable cost per unit and press §.
3. Key in the number of units sold and press -.
4. Key in the fixed cost and press ³ to calculate the gross profit.
To calculate the sales volume needed to achieve a specified gross profit:
RPN Mode:
1. Key in the desired gross profit and press \.
2. Key in the fixed cost and press +.
3. Key in sales price per unit and press \.
4. Key in the variable cost per unit and press -.
5. Press z to calculate the sales volume.
Investment Analysis 55
ALG Mode:
1. Key in the desired gross profit and press +.
2. Key in the fixed cost and press ³.
3. Key in sales price per unit and press -.
4. Key in the variable cost per unit and press z.
5. Press ~~³ to calculate the sales volume.
To calculate the required sales price to achieve a given gross profit at a specified sales
volume:
RPN Mode:
1. Key in the fixed costs and press \.
2. Key in the gross desired and press +.
3. Key in the specified sales volume in units and press z.
4. Key in the variable cost per unit and press + to calculate the required sales price per
unit.
ALG Mode:
1. Key in the fixed costs and press +.
2. Key in the gross desired and press z.
3. Key in the specified sales volume in units and press +.
4. Key in the variable cost per unit and press ³ to calculate the required sales price per
unit.
Example 1: The E.Z. Sells company markets textbooks on salesmanship. The fixed cost
involved in setting up to print the books are $12,000. The variable cost per copy,
including printing and marketing the books are $6.75 per copy. The sales price per copy is
$13.00. How many copies must be sold to break even?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
12000\ 12000³ 12,000.00 Fixed cost.
13\ 13- 13.00 Sales price.
6.75-z 6.75z~~³ 1,920.00 Break-even volume.
56 Investment Analysis
Find the gross profit if 2500 units are sold.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
13\ 13- 13.00 Sales price.
6.75- 6.75§ 6.25 Profit per unit.
2500§ 2500- 15,625.00
12000- 12000³ 3,625.00 Gross profit.
If a gross profit of $4500 is desired at a sales volume of 2500 units, what should the sales
price be?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
12000\ 12000+ 12,000.00 Fixed cost.
4500+ 4500z 16,500.00
2500z 2500+ 6.60
6.75+ 6.75³ 13.35 Sales price per unit to achieve
desired gross profit.
For repeated calculation the following HP 12C Platinum program can be used.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
:3 001, 45 3 :3 001, 45 3
:2 002, 45 2 - 002, 30
- 003, 30 :2 003, 45 2
g(000 004,43,33,000 ³ 004, 36
:4 005, 45 4 g(000 005,43,33,000
§ 006, 20 § 006, 20
:1 007, 45 1 :4 007, 45 4
- 008, 30 - 008, 30
g(000 009,43,33,000 :1 009, 45 1
:5 010, 45 5 ³ 010, 36
:1 011, 45 1 g(000 011,43,33,000
+ 012, 40 :5 012, 45 5
~ 013, 34 + 013, 40
z 014, 10 :1 014, 45 1
g(000 015,43,33,000 z 015, 10
:1 016, 45 1 ~ 016, 34
:5 017, 45 5 ³ 017, 36
+ 018, 40 g(000 018,43,33,000
Investment Analysis 57
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
:4 019, 45 4 :1 019, 45 1
z 020, 10 + 020, 40
:2 021, 45 2 :5 021, 45 5
+ 022, 40 z 022, 10
g(000 023,43,33,000 :4 023, 45 4
fs + 024, 40
:2 025, 45 2
³ 026, 36
g(000 027,43,33,000
fs
REGISTERS
n: Unused I: Unused PV: Unused PMT: Unused
FV: Unused R0: Unused R1: F R
2: V
R3: P R
4: U R
5: GP R
6-R.6: Unused
Program Instructions:
1. Key in the program and store the known variables as follows:
a. Key in the fixed costs, F and press ?1.
b. Key in the variable costs per unit, V and press ?2.
c. Key in the unit price, P (if known) and press ?3.
d. Key in the sales volume, U, in units (if known) and press ?4.
e. Key in the gross profit, GP, (if known) and press ?5.
2. To calculate the sales volume to achieve a desired gross profit:
a. Store values as shown in 1a, 1b, and 1c.
b. Key in the desired gross profit (zero for break even) and press ?5.
c. RPN: Press tg(010t to calculate the required volume.
c. ALG: Press tg(012t to calculate the required volume.
3. To calculate the gross profit at a given sales volume.
a. Store values as shown in 1a, 1b, 1c, and 1d.
b. RPN: Press tg(005t to calculate gross profit.
b. ALG: Press tg(006t to calculate gross profit.
4. To calculate the sales price per unit to achieve a desired gross profit at a specified
sales volume:
a. Store values as shown in 1a, 1b, 1d, and 1e.
b. RPN: Press g(016t to calculate the required sales price.
b. ALG: Press g(019t to calculate the required sales price.
58 Investment Analysis
Example 2: A manufacturer of automotive accessories produces rear view mirrors. A new
line of mirrors will require fixed costs of $35,000 to produce. Each mirror has a variable
cost of $8.25. The price of mirrors is tentatively set at $12.50 each. What volume is
needed to break even?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
35000?1 35000?1 35,000.00 Fixed cost.
8.25?2 8.25?2 8.25 Variable cost.
12.5?3 12.5?3 12.50 Sales price.
0?5 0?5 0.00
tg(010t tg(012t 8,235.29 Break-even volume is between
8,235 and 8,236 units.
What would be the gross profit if the price is raised to $14.00 and the sales volume is
10,000 units?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
14?3 14?3 14.00 Sales price.
F and V are already stored.
10000?4 10000?4 10,000.00 Volume.
tg(005t tg(006t 22,500.00 Gross Profit.
Investment Analysis 59
Operating Leverage
The degree of operating leverage (OL) at a point is defined as the ratio of the percentage
change in net operating income to the percentage change in units sold. The greatest degree
of operating leverage is found near the break-even point where a small change in sales
may produce a very large increase in profits. Likewise, firms with a small degree of
operating leverage are operating farther form the break-even point, and they are relatively
insensitive to changes in sales volume.
The necessary inputs to calculate the degree of operating leverage and fixed costs (F),
sales price per unit (P), variable cost per unit (V) and number of units (U).
The operating leverage may be readily calculated as follows:
RPN Mode:
1. Key in the sales price per unit and press \.
2. Key in the variable cost per unit and press -.
3. Key in the number of units and press §\\.
4. Key in the fixed cost and press -z to obtain the operating leverage.
ALG Mode:
1. Key in the sales price per unit and press -.
2. Key in the variable cost per unit and press §.
3. Key in the number of units and press ³.
4. Key in the fixed cost and press àbÞy to obtain the operating leverage.
Example 1: For the data given in example 1 of the Break-Even Analysis section,
calculate the operating leverage at 2000 units and at 5000 units when the sales price is $13
a copy.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
13\ 13- 13.00 Price per copy.
6.75- 6.75§ 6.25 Profit per copy.
2000§\ 2000³12000
\12000-z àbÞy 25.00 Close to break-even point.
13\ 13- 13.00 Price per copy.
6.75- 6.75§ 6.25 Profit per copy.
5000§\ 5000³12000
\12000-z àbÞy 1.62 Operating further from the
breakeven point and less
sensitive to changes in sales
volume.
60 Investment Analysis
For repeated calculations the following HP 12C Platinum program can be used:
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
:3 001, 45 3 :3 001, 45 3
:2 002, 45 2 - 002, 30
- 003, 30 :2 003, 45 2
§ 004, 20 § 004, 20
\ 005, 36 ~ 005, 34
\ 006, 36 ³ 006, 36
:1 007, 45 1 :1 007, 45 1
- 008, 30 à 008, 24
z 009, 10 b 009, 25
g(000 010,43,33,000 Þ 010, 16
fs y 011, 22
g(000 012,43,33,000
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: Unused R1: F R
2: V
R3: P R
4-R.8: Unused
Program Instructions:
1. Key in the program.
2. Key in and store input variables F, V and P as described in the Break-Even Analysis
program.
3. Key in the sales volume and press t to calculate the operating leverage.
4. To calculate a new operating leverage at a different sales volume, key in the new sales
volume and press t.
Example 2: For the figures given in example 2 of the Break-Even Analysis section,
calculate the operating leverage at a sales volume of 9,000 and 20,000 units if the sales
price is $12.50 per unit.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
35000?1 35000?1 35,000.00 Fixed costs.
8.25?2 8.25?2 8.25 Variable cost.
12.5?3 12.5?3 12.50 Sales price.
9000t 9000t 11.77 Operating leverage near break-
even.
20000t 20000t 1.70 Operating leverage further
from break-even.
Investment Analysis 61
Profit and Loss Analysis
The HP 12C Platinum may be programmed to perform simplified profit and loss analysis
using the standard profit income formula and can be used as a dynamic simulator to
quickly explore ranges of variables affecting the profitability of a marketing operation.
The program operates with net income return and operating expenses as percentages. Both
percentage figures are based on net sales price.
It may also be used to simulate a company wide income statement by replacing list price
with gross sales and manufacturing cost with cost of goods sold.
Any of the five variables: a) list price, b) discount (as a percentage of list price), c)
manufacturing cost, d) operating expense (as a percentage), e) net profit after tax (as a
percentage) may be calculated if the other four are known.
Since the tax rage varies from company to company, provision is made for inputting your
applicable tax rate. The example problem uses a tax rate of 48%.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
:5 001, 45 5 :5 001, 45 5
:6 002, 45 6 z 002, 10
z 003, 10 :6 003, 45 6
:4 004, 45 4 + 004, 40
+ 005, 40 :4 005, 45 4
Þ 006, 16 - 006, 30
:0 007, 45 0 1 007, 1
+ 008, 40 ~ 008, 34
:0 009, 45 0 b 009, 25
z 010, 10 ³ 010, 36
g(000 011,43,33,000 g(000 011,43,33,000
:3 012, 45 3 :3 012, 45 3
:1 013, 45 1 :1 013, 45 1
:2 014, 45 2 :2 014, 45 2
:0 015, 45 0 ~ 015, 34
z 016, 10 - 016, 30
Þ 017, 16 ~ 017, 34
1 018, 1 b 018, 25
+ 019, 40 ³ 019, 36
§ 020, 20 t 020, 31
t 021, 31 g(027 021,43,33,027
z 022, 10 ~ 022, 34
Þ 023, 16 z 023, 10
1 024, 1 ~ 024, 34
62 Investment Analysis
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
+ 025, 40 ³ 025, 36
:0 026, 45 0 :1 026, 45 1
§ 027, 20 ~ 027, 34
g(000 028,43,33,000 à 028, 24
z 029, 10 Þ 029, 16
Þ 030, 16 g(000 030,43,33,000
:1 031, 45 1 :5 031, 45 5
+ 032, 40 z 032, 10
:1 033, 45 1 :6 033, 45 6
z 034, 10 - 034, 30
:0 035, 45 0 ~ 035, 34
§ 036, 20 ~ 036, 34
g(000 037,43,33,000 ³ 037, 36
:5 038, 45 5 g(000 038,43,33,000
:6 039, 45 6 - 039, 30
z 040, 10 :4 040, 45 4
- 041, 30 § 041, 20
g(000 042,43,33,000 :6 042, 45 6
:4 043, 45 5 ³ 043, 36
- 044, 30 g(000 044,43,33,000
:6 045, 45 6 fs
§ 046, 20
g(000 047,43,33,000
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: 100 R1: list price R2: % discount
R3: mfg. cost R4: % op. exp. R5: % net profit R6: 1-% tax
R7-R.3: Unused
Program Instructions:
1. Key in the program and press fCLEARH, then key in 100 and press ?0.
2. RPN: Key in 1 and press \, then key in your appropriate tax rate as a decimal and
press -?6.
2. ALG: Key in 1 and press -, then key in your appropriate tax rate as a decimal and
press ³?6.
3. a. Key in the list price in dollars (if known) and press ?1.
b.
Key in the discount in percent (if known) and press ?2.
c.
Key in the manufacturing cost in dollars (if known) and press ?3.
d.
Key in the operating expense in percent (if known) and press ?4.
e.
Key in the net profit after tax in percent (if known) and press ?5.
Investment Analysis 63
4. To calculate list price:
a. Do steps 2 and 3b, c, d, e above.
b.
RPN: Press :3tz1g(014tzg(000.
b.
ALG: Press :3t~z~³1g(014t
~z~ ³g(000.
5. To calculate discount:
a. Do steps 2 and 3a, c, d, e above.
b.
RPN: Press :3tg(029t.
b.
ALG: Press :3tg(022t.
6. To calculate manufacturing cost:
a. Do steps 2 and 3a, b, d, e, above.
b.
RPN: Press g(013tg(001t§.
b.
ALG: Press g(013tg(001t§~³.
7. To calculate operating expense:
a. Do steps 2 and 3a, b, c, e, above.
b.
RPN: Press g(012ttg(038t.
b.
ALG: Press g(012ttg(031t.
8. To calculate net profit after tax:
a. Do steps 2 and 3a, b, c, d, above.
b.
RPN: Press g(012ttg(043t.
b.
ALG: Press g(012ttg(039t.
Example: What is the net return on an item that is sold for $11.98, discounted through
distribution an average of 35% and has a manufacturing cost of $2.50? The standard
company operating expense is 32% of net shipping (sales) price and tax rate is 48%.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH
100?0 100?0 100.00
1\.48-?6 1-.48³?6 0.52 48% tax rate.
11.98?1 11.98?1 11.98 List price ($).
35?2 35?2 35.00 Discount (%).
2.50?3 2.50?3 2.50 Manufacturing cost ($).
32?4 32?4 32.00 Operating expenses (%).
g(012tt g(012tt 67.90
g(043t g(039t 18.67 Net profit (%).
64 Investment Analysis
If manufacturing expenses increase to $3.25, what is the effect on net profit?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
3.25?3 3.25?3 3.25 Manufacturing cost.
g(012tt g(012tt 58.26
g(043t g(039t 13.66 Net profit reduced to 13.66%
If the manufacturing cost is maintained at $3.25, how high could the overhead (operating
expense) be before the product begins to lose money?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
0?5 0?5 0.00
g(012tt g(012tt 58.26
g(038t g(031t 58.26 Maximum operating expense
(%).
At 32% operating expense and $3.25 manufacturing cost, what should the list price be to
generate 20% net profit?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
20?5 20?5 20.00
:3tz :3t~z~³ 11.00
1g(014tz 1g(014t~z~³ 16.93 List price ($).
What reduction in manufacturing cost would achieve the same result without necessitating
an increase in list price above $11.98?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g(013t g(013t 7.79
g(001t§ g(001t§~³ 2.30 Manufacturing cost ($).
65
Securities and Options
After-Tax Yield
The following HP 12C Platinum program calculates the after-tax yield to maturity of a
bond held for more than one year. The calculation assumes an actual/actual day basis. For
after-tax computations, the interest or coupon payments are considered income, while the
difference between the bond's face value and its purchase price is considered capital gains.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
fCLEARG 001, 42 34 fCLEARG 001, 42 34
?7 002, 44 7 ?7 002, 44 7
d 003, 33 d 003, 33
?6 004, 44 6 ?6 004, 44 6
:2 005, 45 2 :2 005, 45 2
:1 006, 45 1 - 006, 30
- 007, 30 :1 007, 45 1
:4 008, 45 4 - 008, 30
b 009, 25 :4 009, 45 4
:2 010, 45 2 b 010, 25
~ 011, 34 + 011, 40
- 012, 30 :1 012, 45 1
Æ 013, 26 ³ 013, 36
2 014, 2 b 014, 25
z 015, 10 ?0 015, 44 0
?0 016, 44 0 :3 016, 45 3
:3 017, 45 3 - 017, 30
:5 018, 45 5 :5 018, 45 5
b 019, 25 b 019, 25
- 020, 30 z 020, 10
:0 021, 45 0 :0 021, 45 0
z 022, 10 P 022, 14
P 023, 14 :1 023, 45 1
:1 024, 45 1 z 024, 10
:0 025, 45 0 :0 025, 45 0
z 026, 10 $ 026, 13
$ 027, 13 :6 027, 45 6
:6 028, 45 6 :7 028, 45 7
:7 029, 45 7 fS 029, 42 22
66 Securities and Options
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fS 030, 42 22 g(000 030,43,33,000
g(000 031,43,33,000 fs
fs
REGISTERS
n: Unused i: Yield PV: Used PMT: Used
FV: 0 R0: Used R1: Purchase price R2: Sales price
R3: Coupon rate R4: Capital rate R5: Income rate R6: Used
R7: Used R8-R.5: Unused
Program Instructions:
1. Key in the program.
2. Key in the purchase price and press ?1.
3. Key in the sales price and press ?2.
4. Key in the annual coupon rate (as a percentage) and press ?3.
5. Key in capital gains tax rate (as a percentage) and press ?4.
6. Key in the income tax rate (as a percentage) and press ?5.
7. Press gÕ.
8. Key in the purchase date (MM.DDYYYY) and press \(³).
9. Key in the assumed sell date (MM.DDYYYY) and press t to find the after-tax
yield (as a percentage).
10. For the same bond but different date return to step 8.
11. For a new case return to step 2.
Example: You can buy a 7% bond on October 1, 2003 for $70 and expect to sell it in 5
years for $90. What is your net (after-tax) yield over the 5-year period if interim coupon
payments are considered as income, and your tax bracket is 50%?
(One-half of the long term capital gain is taxable at 50%, so the tax on capital gains alone
is 25%)
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
70?1 70?1 70.00 Purchase price.
90?2 90?2 90.00 Selling price.
7?3 7?3 7.00 Annual coupon rate.
25?4 25?4 25.00 Capital gains tax rate.
50?5 50?5 50.00 Income tax rate.
gÕ gÕ
10.012003\ 10.012003³ 10.01 Purchase Date.
10.012008t 10.012008t 8.53 % after tax yield.
Securities and Options 67
Discounted Notes
A note is a written agreement to pay a sum of money plus interest at a certain rate. Notes
do not have periodic coupons, since all interest is paid at maturity.
A discounted note is a note that is purchased below its face value. The following HP 12C
Platinum program finds the price and/or yield* of a discounted note.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
:1 001, 45 1 :1 001, 45 1
:2 002, 45 2 :2 002, 45 2
gÒ 003, 43 26 gÒ 003, 43 26
:3 004, 45 3 z 004, 10
z 005, 10 :3 005, 45 3
:5 006, 45 5 § 006, 20
b 007, 25 :5 007, 45 5
1 008, 1 ³ 008, 36
~ 009, 34 :4 009, 45 4
- 010, 30 - 010, 30
:4 011, 45 4 ~ 011, 34
§ 012, 20 b 012, 25
?5 013, 44 5 ³ 013, 36
t 014, 31 ?5 014, 44 5
:1 015, 45 1 t 015, 31
:2 016, 45 2 :1 016, 45 1
gÒ 017, 43 26 :2 017, 45 2
:3 018, 45 3 gÒ 018, 43 26
~ 019, 34 :5 019, 45 5
z 020, 10 :4 020, 45 4
:4 021, 45 4 à 021, 24
:5 022, 45 5 ~ 022, 34
z 023, 10 d 023, 33
1 024, 1 z 024, 10
- 025, 30 ~ 025, 34
§ 026, 20 § 026, 20
Æ 027, 26 :3 027, 45 3
2 028, 2 ³ 028, 36
§ 029, 20 g(000 029,43,33,000
g(000 030,43,33,000 fs
fs
* The yield is a reflection of the return on an investment.
68 Securities and Options
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: Unused R1: Settl. date R2: Mat. Date
R3: 360 or 360 R4: redemp. Value R5: dis./price R6-R.5: Unused
Program Instructions:
1. Key in the program.
2. Press gÕ.
3. Key in the settlement date (MM.DDYYYY) and press ?1.
4. Key in the maturity date (MM.DDYYYY) and press ?2.
5. Key in the number of days in a year (360 or 365) and press ?3.
6. Key in the redemption value per $100 and press ?4.
7. To calculate the purchase price:
a. Key in the discount rate and press ?5.
b. Press t to calculate the purchase price.
c. Press t to calculate the yield.
d. For a new case, go to step 3.
8. To calculate the yield when the price is known:
a. Key in the price and press ?5.
b. RPN: Press g(015t to calculate the yield.
b. ALG: Press g(016t to calculate the yield.
c. For a new case, go to step 3.
Example 1: Calculate the price and yield on this bill: settlement date October 8, 2002;
maturity date March 21, 2003; discount rate 7.80%. Compute on a 360 day basis.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
gÕ gÕ
10.082002?1 10.082002?1 10.08 Settlement date.
3.212003?2 3.212003?2 3.21 Maturity date.
360?3 360?3 360.00 360 day basis.
100?4 100?4 100.00 Redemption value per $100.
7.8?5 7.8?5 7.80 Discount rate.
t t 96.45 Price.
t t 8.09 Yield.
Securities and Options 69
Example 2: Determine the yield of this security; settlement date June 25, 2002; maturity
date September 10, 2002; price $99.45; redemption value $101.33. Assume 360 day basis.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
6.252002?1 6.252002?1 6.25 Settlement date.
9.102002?2 9.102002?2 9.10 Maturity date.
360?3 360?3 360.00 360 day basis.
101.33?4 101.33?4 101.33 Redemption value per $100.
99.45?5 99.45?5 99.45 Price.
g(015t g(016t 8.84 Yield.
Black-Scholes Formula for Valuing European
Options
This program implements the Black-Scholes formula which has been used extensively in
option markets worldwide since its publication in the early 1970’s. The five inputs are
simply keyed into the five financial variables and then t displays the call option value,
and ~ shows the put option value. The option values produced are accurate to at least
the nearest cent for asset and strike prices under $100.
Reference: Hutchins, 2003, Black-Scholes takes over the HP12C, HPCC (www.hpcc.org)
DataFile,V22,N3 pp13-21.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
:n 001, 45 11 :n 001, 45 11
:¼ 002, 45 12 § 002, 20
b 003, 25 :¼ 003, 45 12
Þ 004, 16 b 004, 25
g> 005, 43 22 ³ 005, 36
:M 006, 45 15 Þ 006, 16
§ 007, 20 g> 007, 43 22
?4 008, 44 4 § 008, 20
~ 009, 34 :M 009, 45 15
gr 010, 43 21 ³ 010, 36
:P 011, 45 14 ?4 011, 44 4
b 012, 25 :n 012, 45 11
?3 013, 44 3 gr 013, 43 21
:$ 014, 45 13 § 014, 20
:4 015, 45 4 :P 015, 45 14
z 016, 10 b 016, 25
70 Securities and Options
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
g° 017, 43 23 ³ 017, 36
~ 018, 34 ?3 018, 44 3
z 019, 10 :$ 019, 45 13
gF 020, 43 40 z 020, 10
2 021, 2 :4 021, 45 4
?5 022, 44 5 ³ 022, 36
z 023, 10 g° 023, 43 23
+ 024, 40 z 024, 10
?6 025, 44 6 ~ 025, 34
:3 026, 45 3 ³ 026, 36
- 027, 30 :3 027, 45 3
?3 028, 44 3 z 028, 10
\ 029, 36 2 029, 2
§ 030, 20 ?5 030, 44 5
gr 031, 43 21 + 031, 40
gF 032, 43 40 ~ 032, 34
2 033, 2 - 033, 30
z 034, 10 ?6 034, 44 6
Þ 035, 16 :3 035, 45 3
g> 036, 43 22 ³ 036, 36
~ 037, 34 ?3 037, 44 3
3 038, 3 g’ 038, 43 20
. 039, 48 z 039, 10
0 040, 0 2 040, 2
0 041, 0 ³ 041, 36
6 042, 6 Þ 042, 16
z 043, 10 g> 043, 43 22
1 044, 1 :3 044, 45 3
+ 045, 40 g’ 045, 43 20
y 046, 22 gr 046, 43 21
§ 047, 20 z 047, 10
gF 048, 43 40 3 048, 3
gF 049, 43 40 . 049, 48
1 050, 1 0 050, 0
8 051, 8 0 051, 0
7 052, 7 6 052, 6
§ 053, 20 + 053, 40
2 054, 2 1 054, 1
4 055, 4 ³ 055, 36
- 056, 30 y 056, 22
§ 057, 20 ?2 057, 44 2
8 058, 8 § 058, 20
7 059, 7 ~ 059, 34
+ 060, 40 ³ 060, 36
Securities and Options 71
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
§ 061, 20 1 061, 1
. 062, 48 8 062, 8
2 063, 2 7 063, 7
b 064, 25 § 064, 20
:3 065, 45 3 :2 065, 45 2
~ 066, 34 - 066, 30
?3 067, 44 3 2 067, 2
O 068, 35 4 068, 4
~ 069, 34 § 069, 20
go 070, 43 34 :2 070, 45 2
g(077 071,43,33,077 + 071, 40
1 072, 1 8 072, 8
?-3 073,44 30 3 7 073, 7
Þ 074, 16 § 074, 20
?§3 075,44 20 3 ~ 075, 34
~ 076, 34 § 076, 20
:5 077, 45 5 . 077, 48
gm 078, 43 35 2 078, 2
g(089 079,43,33,089 b 079, 25
:6 080, 45 6 ³ 080, 36
:3 081, 45 3 :3 081, 45 3
:4 082, 45 4 ~ 082, 34
§ 083, 20 ?3 083, 44 3
?6 084, 44 6 O 084, 35
O 085, 35 ~ 085, 34
?5 086, 44 5 go 086, 43 34
~ 087, 34 g(093 087,43,33,093
g(028 088,43,33,028 1 088, 1
~ 089, 34 ?-3 089,44 30 3
:3 090, 45 3 Þ 090, 16
:$ 091, 45 13 ?§3 091,44 20 3
?-4 092,44 30 4 ~ 092, 34
§ 093, 20 :5 093, 45 5
:6 094, 45 6 gm 094, 43 35
- 095, 30 g(106 095,43,33,106
?+4 096,44 40 4 :6 096, 45 6
:4 097, 45 4 :3 097, 45 3
~ 098, 34 § 098, 20
?5 099, 44 5 :4 099, 45 4
fs ³ 100, 36
72 Securities and Options
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
?6 101, 44 6
O 102, 35
?5 103, 44 5
~ 104, 34
g(037 105,43,33,037
~ 106, 34
:$ 107, 45 13
?-4 108,44 30 4
§ 109, 20
:3 110, 45 3
- 111, 30
:6 112, 45 6
³ 113, 36
?+4 114,44 40 4
:4 115, 45 4
~ 116, 34
?5 117, 44 5
g(000 118,43,33,000
fs
REGISTERS
n: Term to expiry i: Interest rate (%) PV: Stock price PMT: Volatility (%)
FV: Strike price R0: Unused R1: Unused R2: Unused
R3: N(d1) R4: Put value R5: Call value R6: Q·N(d2)
R7-R.9: Unused
Note: The n, i and PMT values must all be based on the same time unit (for example: n is
measured in years or months and i and PMT are rates per year or per month). i is a
continuous percentage rate. PMT is the standard deviation of the continuous percentage
stock return (as observed over the time unit). For sensible output, all inputs should be
positive. The PMT=0 case can be simulated by using a PMT arbitrarily close to 0.
Program Instructions
1. Key in the program.
2. Enter the five inputs into the five financial registers. These values are preserved by the
program.
a. Key in the unexpired term of the option and press n.
b. Key in the risk-free interest rate as a percentage and press ¼.
c. Key in the current (or spot) stock price and press $.
d. Key in the volatility assumption as a percentage and press P.
e. Key in the strike price and press M.
3. Press R/S. The Call value is displayed. Press ~ to see the Put value.
Securities and Options 73
Example 1: An option has 6 months to run and a strike price of $45. Find Call and Put
values assuming a spot price of $52, return volatility of 20.54% per month and a risk-free
interest rate of ½% per month. Show how to re-scale n, i and PMT to use a yearly time
unit, and how to re-scale them back again to the original monthly basis.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
6n 6n 6.00 Time to expiry (months).
.5¼ .5¼ 0.50 Interest rate (% per month).
52$ 52$ 52.00 Stock price.
20.54P 20.54P 20.54 Volatility (% per month).
45M 45M 45.00 Strike price.
t t 14.22 Call value.
~ ~ 5.89 Put value.
:gAn :gAn
0.50 Years to expiry.
:gC¼ :gC¼
6.00 Yearly interest rate %.
:P
12gr§P
:P§
12grP
71.15
Yearly volatility %.
t t 14.22 Call value (unchanged).
:ngA :ngA
6.00 Months to expiry.
:¼gC :¼gC
0.50 Monthly interest rate %.
:P
12grzP
:Pz
12grP
20.54
Monthly volatility %.
The next example is Example 12.7 from Options, Futures, and Other Derivatives (5th
Edition) by John C. Hull (Prentice Hall, 2002).
Example 2: The stock price six months from the expiration of an option is $42, the
exercise price of the option is $40, the risk-free interest rate is 10% per annum, and the
volatility is 20% per annum. Find Call and Put values.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
.5n .5n 0.50 Time to expiry (years).
10¼ 10¼ 10.00 Interest rate (% per year).
42$ 42$ 42.00 Stock price.
20P 20P 20.00 Volatility (% per year).
40M 40M 40.00 Strike price.
t t 4.76 Call value.
~ ~ 0.81 Put value.
74
Forecasting
Simple Moving Average
Moving averages are often useful in recording of forecasting sales figures, expenses or
manufacturing volume. There are many different types of moving average calculations.
An often used, straightforward method of calculation is presented here.
In a moving average a specified number of data points are averaged. When there is a new
piece of input data, the oldest piece of data is discarded to make room for the latest input.
This replacement scheme makes the moving average a valuable tool in following trends.
The fewer the number of data points, the more trend sensitive the average becomes. With
a large number of data points, the average behaves more like a regular average,
responding slowly to new input data.
A simple moving average may be calculated with your HP 12C Platinum as follows.
1. Press fCLEARH.
2. Key in the first m data points (where m is the number of data points in the average)
and press _ after each entry.
3. Press gÖ to obtain the first average.
4. Key in the oldest (first value) entered in step 2 and press g^.
5. Key in the newest data point (m + 1) and press _.
6. Press gÖ to obtain the next value of the moving average.
7. Repeat steps 4 through 5 for the remaining data.
Example 1: An electronics sales firm wished to calculate a 3-month moving average for
the dollar volume of components sold each month. Sales for the first six months of this
year were:
January $211,570 April 131,760
February 112,550 May 300,500
March 190,060 June 271,120
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH 0.00
211570_ 211570_ 1.00
112550_ 112550_ 2.00
190060_ 190060_ 3.00
gÖ gÖ 171,393.33 3-month average for March.
Forecasting 75
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
211570g^ 211570g^ 2.00
131760_ 131760_ 3.00
gÖ gÖ 144,790.00 3-month average for April.
112550g^ 112550g^ 2.00
300500_ 300500_ 3.00
gÖ gÖ 207,440.00 3-month average for May.
190060g^ 190060g^ 2.00
271120_ 271120_ 3.00
gÖ gÖ 234,460.00 3-month average for June.
For repeated calculations the following HP 12C Platinum program can be used for up to a
12 element moving average:
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
:1 001, 45 1 :1 001, 45 1
:2 002, 45 2 + 002, 40
?1 003, 44 1 :2 003, 45 2
+ 004, 40 ?1 004, 44 1
:3 005, 45 3 + 005, 40
?2 006, 44 2 :3 006, 45 3
+3 007, 40 ?23 007, 44 2
:4 008, 45 4 + 008, 40
?3 009, 44 3 :4 009, 45 4
+4 010, 40 ?34 010, 44 3
:5 011, 45 5 + 011, 40
?4 012, 44 4 :5 012, 45 5
+5 013, 40 ?45 013, 44 4
:6 014, 45 6 + 014, 40
?5 015, 44 5 :6 015, 45 6
+6 016, 40 ?56 016, 44 5
:7 017, 45 7 + 017, 40
?6 018, 44 6 :7 018, 45 7
+7 019, 40 ?67 019, 44 6
:8 020, 45 8 + 020, 40
?7 021, 44 7 :8 021, 45 8
+8 022, 40 ?78 022, 44 7
:9 023, 45 9 + 023, 40
? 024, 44 8 :9 024, 45 9
+9 025, 40 ?89 025, 44 8
:.0 026,45 48 0 + 026, 40
76 Forecasting
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
?9 027, 44 9 :.0 027,45 48 0
+10 028, 40 ?910 028, 44 9
:.1 029,45 48 1 + 029, 40
?.0 030,44 48 0 :.1 030,45 48 1
+11 031, 40 ?.011 031,44 48 0
:.2 032,45 48 2 + 032, 40
?.1 033,44 48 1 :.2 033,45 48 2
+12 034, 40 ?.112 034,44 48 1
:0 035, 45 0 z 035, 10
z 036, 10 :0 036, 45 0
t 037, 31 ³ 037, 36
?m* 038, 44 -- t 038, 31
g(001 039,43,33,001 ?m* 039, 44 --
fs g(001 040,43,33,001
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: m R
1: X1 R
2: X2
R3: X3 R
4: X4 R
5: X5 R
6: X6
R7: X7 R
8: X8 R
9: X9 R
.0: X.0
R.1: X11 R
.2: X12 R
.3-R.4: Unused
This program can be used for a moving average of 2 to 12 elements. It may be shortened
considerably for moving averages with less than 12 elements. To do this, key in the
program, as shown, from line 01 until you reach a + (ALG: a ? command)
superscripted with the number of elements you desire. Key in this line, then skip the rest
of the program down to line 35. Then key in lines 035 through 039 (ALG:040), being sure
to specify the register number at line 038 (ALG:039), ? m, corresponding to the
number of elements you are using. (For instance, for a 5 element moving average, key in
lines 01 through 13 then go to line 35 in the listing and key in the balance of the program.
Obviously the program listing line 38 (ALG:039), ? m becomes the displayed line 017,
?5 in RPN and 018, ?5 in ALG).
* At step 038 (ALG:039), m=number of elements in the moving average, i.e. for a 5 element moving
average line 038 (ALG:039) would be ?5 and for a 12 element average line 38 (ALG:039) would
be ?.2
Forecasting 77
Program Instructions:
1. Key in the program.
2. Press fCLEARH. Key in the number of elements, m, and press ?0.
3. Key in the first data point and press ?1.
4. Key in the second data point and press ?2.
5. Continue as above, keying in and storing each data point in its appropriate register
until m data points have been stored.
6. Press g(000t to calculate the first moving average.
7. Key in the next data point and press t to calculate the next moving average.
8. Repeat step 7 for each new data point.
Example 2: Calculate the 3-element moving average for the data given in example 1.
Your modified program listing will look like this:
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
:1 001, 45 1 :1 001, 45 1
:2 002, 45 2 + 002, 40
?1 003, 44 1 :2 003, 45 2
+ 004, 40 ?1 004, 44 1
:3 005, 45 3 + 005, 40
?2 006, 44 2 :3 006, 45 3
+ 007, 40 ?2 007, 44 2
:0 008, 45 0 z 008, 10
z 009, 10 :0 009, 45 0
t 010, 31 ³ 010, 36
?3 011, 44 3 t 011, 31
g(001 012,43,33,001 ?3 012, 44 3
fs g(001 013,43,33,001
fs
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH 0.00
3?0 3?0 3.00
211570?1 211570?1 211,570.00
112550?2 112550?2 112,550.00
190060?3 190060?3 190,060.00
g(000t g(000t 171,393.33 3-month average for March.
131760t 131760t 144,790.00 3-month average for April.
78 Forecasting
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
300500t 300500t 207,440.00 3-month average for May.
271120t 271120t 234,460.00 3-month average for June.
Seasonal Variation Factors Based on
Centered Moving Averages
Seasonal variation factors are useful concepts in many types of forecasting. There are
several methods of developing seasonal moving averages, on the of more common ways
being to calculate them as a ratio of the periodic value to a centered moving average for
the same period.
For instance, to determine the sales for the 3rd quarter of a given year a centered moving
average for that quarter would be calculated from sales figures from the 1st, 2nd, 3rd and
4th quarters of the year and the 1st quarter of the following year. The seasonal variation
factor for that 3rd quarter would then be the ratio of the actual sales in the 3rd quarter to
the centered moving average for that quarter.
While quarterly seasonal variations are commonly used, the HP 12C Platinum can also be
programmed to calculate monthly seasonal variations using a centered 12 month moving
average. Programs for both of these calculations are represented here:
An HP 12C Platinum program to calculate the quarterly seasonal variations based on a
centered 4-point moving average is:
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
:1 001, 45 1 :1 001, 45 1
2 002, 2 z 002, 10
z 003, 10 2 003, 2
:2 004, 45 2 + 004, 40
?1 005, 44 1 :2 005, 45 2
+ 006, 40 ?1 006, 44 1
:3 007, 45 3 + 007, 40
?2 008, 44 2 :3 008, 45 3
+ 009, 40 ?2 009, 44 2
:4 010, 45 4 + 010, 40
?3 011, 44 3 :4 011, 45 4
+ 012, 40 ?3 012, 44 3
:5 013, 45 5 ³ 013, 36
?4 014, 44 4 :5 014, 45 5
2 015, 2 ?4 015, 44 4
z 016, 10 z 016, 10
+ 017, 40 2 017, 2
Forecasting 79
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
4 018, 4 + 018, 40
z 019, 10 ~ 019, 34
t 020, 31 z 020, 10
:2 021, 45 2 4 021, 4
Z 022, 23 ³ 022, 36
t 023, 31 t 023, 31
?5 024, 44 5 :2 024, 45 2
g(001 025,43,33,001 Z 025, 23
fs t 026, 31
?5 027, 44 5
g(001 028,43,33,001
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: n R
1: X1 R
2: X2
R3: X3 R
4: X4 R
5: X5 R
6-R.6: Unused
Program Instructions:
1. Key in the program.
2. Press fCLEARH.
3. Key in the quarterly sales figures starting with the first quarter:
a. Key in 1st quarter sales and press ?1.
b. Key in 2nd quarter sales and press ?2.
c. Key in 3rd quarter sales and press ?3.
d. Key in 4th quarter sales and press ?4.
e. Key in the 1st quarter sales for the next year and press ?5.
4. Press g(000t to calculate the centered moving average for the 3rd quarter of
the first year.
5. Press t to calculate the seasonal variation for this quarter.
6. Key in the next quarter's sales and press t to calculate the moving average for the
next quarter.
7. Press t to calculate the seasonal variation.
8. Repeat steps 6 and 7 for the balance of the data.
80 Forecasting
Example: Econo-Wise Home Appliance Company had quarterly sales for the years 2000
thru 2002 as follows:
Sales (IN $K)
Quarterly 1st 2nd 3rd 4th
2000 397 376 460 501
2001 455 390 530 560
2002 513 434 562 593
Find the centered 4-quarter moving average and seasonal variation factor for each quarter.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH 0.00
397?1 397?1 397.00
376?2 376?2 376.00
460?3 460?3 460.00
501?4 501?4 501.00
455?5 455?5 455.00
g(000t g(000t 440.75 Centered 4-element average for
3rd quarter, 2000.
t t 104.37 Seasonal variation factor.
390t 390t 449.75 4th quarter, 2000.
t t 111.40
530t 530t 460.25 1st quarter, 2001.
t t 98.86
560t 560t 476.38 2nd quarter, 2001.
t t 81.87
513t 513t 491.00 3rd quarter, 2001.
t t 107.94
434t 434t 503.75 4th quarter, 2001.
t t 111.17
562t 562t 513.25 1st quarter, 2002.
t t 99.95
593t 593t 521.38 2nd quarter, 2002.
t t 83.24
Now, what is the average of each quarter's seasonal variation for the two years?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEAR² fCLEAR² 0.00
98.86_ 98.86_ 1.00
99.95_ 99.95_ 2.00
gÖ gÖ 99.41 1st quarter average seasonal
variation, %.
Forecasting 81
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEAR² fCLEAR² 0.00
81.87_ 81.87_ 1.00
83.24_ 83.24_ 2.00
gÖ gÖ 82.56 2nd quarter average seasonal
variation, %.
fCLEAR² fCLEAR² 0.00
104.37_ 104.37_ 1.00
107.94_ 107.94_ 2.00
gÖ gÖ 106.16 3rd quarter average seasonal
variation, %.
fCLEAR² fCLEAR² 0.00
111.4_ 111.4_ 1.00
111.17_ 111.17_ 2.00
gÖ gÖ 111.29 4th quarter average seasonal
variation, %.
An HP 12C Platinum program to calculate a centered 12 month moving average and
seasonal variation factor is as follows:
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
:1 001, 45 1 :1 001, 45 1
2 002, 2
z 002, 10
z 003, 10 2 003, 2
:2 004, 45 2 + 004, 40
?1 005, 44 1 :2 005, 45 2
+ 006, 40 ?1 006, 44 1
:3 007, 45 3 + 007, 40
?2 008, 44 2 :3 008, 45 3
+ 009, 40 ?2 009, 44 2
:4 010, 45 4 + 010, 40
?3 011, 44 3 :4 011, 45 4
+ 012, 40 ?3 012, 44 3
:5 013, 45 5 + 013, 40
?4 014, 44 4 :5 014, 45 5
+ 015, 40 ?4 015, 44 4
:6 016, 45 6 + 016, 40
?5 017, 44 5 :6 017, 45 6
+ 018, 40 ?5 018, 44 5
:7 019, 45 7 + 019, 40
?6 020, 44 6 :7 020, 45 7
82 Forecasting
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
+ 021, 40 ?6 021, 44 6
:8 022, 45 8 + 022, 40
?7 023, 44 7 :8 023, 45 8
+ 024, 40 ?7 024, 44 7
:9 025, 45 9 + 025, 40
?8 026, 44 8 :9 026, 45 9
+ 027, 40 ?8 027, 44 8
:.0 028,45 48 0 + 028, 40
?9 029, 44 9 :.0 029,45 48 0
+ 030, 40 ?9 030, 44 9
:.1 031,45 48 1 + 031, 40
?.0 032,44 48 0 :.1 032,45 48 1
+ 033, 40 ?.0 033,44 48 0
:.2 034,45 48 2 + 034, 40
?.1 035,44 48 1 :.2 035,45 48 2
+ 036, 40 ?.1 036,44 48 1
:.3 037,45 48 3 ³ 037, 36
?.2 038,44 48 2 :.3 038,45 48 3
2 039, 2 ?.2 039,44 48 2
z 040, 10 z 040, 10
+ 041, 40 2 041, 2
:0 042, 45 0 + 042, 40
z 043, 10 ~ 043, 34
t 044, 31 z 044, 10
:6 045, 45 6 :0 045, 45 0
Z 046, 23 ³ 046, 36
t 047, 31 t 047, 31
?.3 048,44 48 3 :6 048, 45 6
g(001 048,43,33,001 Z 049, 23
fs t 050, 31
?.3 051,44 48 3
g(001 052,43,33,001
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: n R
1: X1 R
2: X2
R3: X3 R
4: X4 R
5: X5 R
6: X6
R7: X7 R
8: X8 R
9: X9 R
.0: X10
R.1: X11 R
.2: X12 R
.3: X13
Forecasting 83
Program Instructions:
1. Key in the program.
2. Press fCLEARH.
3. Key in 12 and press ?0.
4. Key in the values for the first 13 months, storing them one at a time in registers 1
through .3; i.e.
Key in the 1st month and press ?1.
Key in the 2nd month and press ?2, etc.,
Key in the 10th month and press ?.0, etc.,
Key in the 13th month and press ?.3.
5. Press g(000t to calculate the centered moving average for the 7th month.
6. Press t to calculate the seasonal variation for that month.
7. Key in the value for the next month (14th) and press t to calculate the moving
average for the next month (8th).
8. Repeat steps 6 and 7 for the balance of the data.
These programs may be customized by the user for different types of centered moving
averages. Inspection of the programs will show how they can be modified.
Gompertz Curve Trend Analysis
A useful curve for evaluating sales trends, etc., is the Gompertz curve. This is a "growth"
curve having a general "S" shape and may be used to describe series of data where the
early rate of growth is small, then accelerates for a period of time and then slows again as
the time grows long. The sales curve for many products follow this trend during the
introductory, growth and maturity phases.
The data points to be fit to a Gompertz curve should be equally spaced along the x (or
time) axis and all the data points must be positive. The points are divided serially into 3
groups for data entry.
The following HP 12C Platinum program processes the data, fits it to a Gompertz curve
and calculates estimated values for future data points. The 3 constants which characterize
the curve are available to the user if desired.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
g° 001, 43 23 g° 001, 43 23
?+3 002,44 40 3 ?+3 002,44 40 3
d 003, 33 d 003, 33
84 Forecasting
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
g° 004, 43 23 g° 004, 43 23
?+2 005,44 40 2 ?+2 005,44 40 2
d 006, 33 d 006, 33
g° 007, 43 23 g° 007, 43 23
?+1 008,44 40 1 ?+1 008,44 40 1
1 009, 1 1 009, 1
?+4 010,44 40 4 ?+4 010,44 40 4
:4 011, 45 4 :4 011, 45 4
g(000 012,43,33,000 g(000 012,43,33,000
:3 013, 45 3 :2 013, 45 2
:2 014, 45 2 - 014, 30
- 015, 30 :1 015, 45 1
:2 016, 45 2 ³ 016, 36
:1 017, 45 1 ?8 017, 44 8
- 018, 30 :3 018, 45 3
z 019, 10 - 019, 30
:4 020, 45 4 :2 020, 45 2
y 021, 22 z 021, 10
q 022, 21 ?9 022, 44 9
?6 023, 44 6 ~ 023, 34
:1 024, 45 1 ³ 024, 36
:3 025, 45 3 q 025, 21
§ 026, 20 :4 026, 45 4
:2 027, 45 2 y 027, 22
\ 028, 36 ³ 028, 36
§ 029, 20 ?6 029, 44 6
- 030, 30 :9 030, 45 9
:1 031, 45 1 - 031, 30
:3 032, 45 3 :8 032, 45 8
+ 033, 40 ³ 033, 36
:2 034, 45 2 :1 034, 45 1
2 035, 2 § 035, 20
§ 036, 20 :3 036, 45 3
- 037, 30 - 037, 30
z 038, 10 :2 038, 45 2
:4 039, 45 4 g’ 039, 43 20
z 040, 10 z 040, 10
g> 041, 43 22 ~ 041, 34
?7 042, 44 7 z 042, 10
:6 043, 45 6 :4 043, 45 4
1 044, 1 ³ 044, 36
- 045, 30 g> 045, 43 22
:6 046, 45 6 ?7 046, 44 7
Forecasting 85
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
:4 047, 45 4 :6 047, 45 6
q 048, 21 q 048, 21
1 049, 1 :4 049, 45 4
- 050, 30 - 050, 30
\ 051, 36 1 051, 1
§ 052, 20 ³ 052, 36
z 053, 10 g’ 053, 43 20
:6 054, 45 6 1 054, 1
z 055, 10 - 055, 30
:2 056, 45 2 :6 056, 45 6
:1 057, 45 1 y 057, 22
- 058, 30 § 058, 20
§ 059, 20 :8 059, 45 8
g> 060, 43 22 z 060, 10
?5 061, 44 5 ~ 061, 34
t 062, 31 ³ 062, 36
:6 063, 45 6 g> 063, 43 22
~ 064, 34 ?5 064, 44 5
q 065, 21 t 065, 31
:5 066, 45 5 :6 066, 45 6
~ 067, 34 q 067, 21
q 068, 21 ~ 068, 34
:7 069, 45 7 ³ 069, 36
§ 070, 20 :5 070, 45 5
g(062 071,43,33,062 q 071, 21
fs ~ 072, 34
§ 073, 20
:7 074, 45 7
³ 075, 36
g(065 076,43,33,065
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: Unused R1: S1 R
2: S2
R3: S3 R
4: n R
5: a R
6: b
R7: c R
8-R.0: Unused
Program Instructions:
1. Key in the program and press fCLEARH.
2. Divide the data points to be input into 3 equal consecutive groups. Label them Groups
I, II and III for convenience.
86 Forecasting
3. Key in the first point of group I and press \(³)
4. Key in the first point of group II and press \(³).
5. Key in the first point of group III and press t.
6. Repeat steps 3, 4, and 5 for the balance of the data in each group. After executing step
5 the display shows how many sets of data have been entered.
7. To fit the data to a Gompertz curve, press g(013t . The resultant display is
the curve constant "a". Constants "b" and "c" may be obtained by pressing :6 and
:7 respectively. The display may need adjusting to see significant digits.
8. To calculate a projected value, key in the number of the period and press t.
9. Repeat step 8 for each period desired.
Example: The X-presso Company marked a revolutionary new coffee brewing machine
in 1990. Sales grew at a steady pace for several years, then began to slow. The sales
records for the first 9 years of the product's life were as follows.
Year Sales($K) Year Sales($K)
1 18 6 260
2 41 7 282
3 49 8 322
4 151 9 340
5 188
What are the projected sales volumes for this product in its 10th and 12th year? What is
the maximum yearly sales volume for this product if the present trend continues? What
annual sales rate would the curve have predicted for the 5th year of the product's life?
(Arrange the data as follows:)
Group I Group II Group III
18 151 282
41 188 322
49 260 340
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH 0.00
18\ 18³ 18.00
151\ 151³ 151.00
282t 282t 1.00
41\ 41³ 41.00
188\ 188³ 188.00
322t 322t 2.00
49\ 49³ 49.00
260\ 260³ 260.00
340t 340t 3.00 Total number of entries.
Forecasting 87
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g(013t g(013t 0.004 a
:6 :6 0.65 b
:7 :7 373.92 c
10t 10t 349.09 Sales in 10th year, (in $K).
12t 12t 363.36 Sales in 12th year, (in $K).
100t 100t 373.92 Maximum annual sales
(after very long product
life).
5t 5t 202.60 Sales in 5th year (actual
sales were $188K).
Forecasting with Exponential Smoothing
A common method for analyzing trends in sales, inventory and securities is the moving
average. Exponential smoothing is a version of the weighted moving average which is
readily adaptable to programmable calculator forecasting.
Exponential smoothing is often used for short term sales and inventory forecasts. Typical
forecast periods are monthly or quarterly. Unlike a moving average, exponential
smoothing does not require a great deal of historical data. However , it should not be used
with data which has more than a moderate amount of up or down trend.
When using exponential smoothing, a smoothing factor is chosen which affects the
sensitivity of the average much the same way as the length of the standard moving
average period. The correspondence between the two techniques can be represented by
the formula:
1
2
+
=n
α
where α is the exponential smoothing factor (with values from 0 to 1) and n is the length
of the standard moving average. As the equation shows, the longer the moving average
period, the smaller the equivalent and the less sensitive the average becomes to
fluctuations in current values.
88 Forecasting
Forecasting with exponential smoothing involves selecting the best smoothing factor
based on historical data and then using the factor for updating subsequent data and
forecasting. This procedure uses the following HP 12C Platinum program:
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
\ 001, 36 ?7 001, 44 7
\ 002, 36 - 002, 30
:6 003, 45 6 :6 003, 45 6
- 004, 30 ³ 004, 36
\ 005, 36 t 005, 31
§ 006, 20 g’ 006, 43 20
?+4 007,44 40 4 ?+4 007,44 40 4
gF 008, 43 40 :7 008, 45 7
t 009, 31 § 009, 20
d 010, 33 :0 010, 45 0
d 011, 33 ³ 011, 36
:0 012, 45 0 :2 012, 45 2
§ 013, 20 § 013, 20
:2 014, 45 2 :1 014, 45 1
:1 015, 45 1 + 015, 40
§ 016, 20 ~ 016, 34
+ 017, 40 - 017, 30
:2 018, 45 2 :2 018, 45 2
Þ 019, 16 § 019, 20
~ 020, 34 ?+2 020,44 40 2
?2 021, 44 2 :0 021, 45 0
+ 022, 40 ³ 022, 36
:0 023, 45 0 :3 023, 45 3
§ 024, 20 § 024, 20
:1 025, 45 1 :1 025, 45 1
:3 026, 45 3 + 026, 40
§ 027, 20 ~ 027, 34
+ 028, 40 z 028, 10
?3 029, 44 3 ?3 029, 44 3
:1 030, 45 1 :0 030, 45 0
§ 031, 20 + 031, 40
:0 032, 45 0 :2 032, 45 2
z 033, 10 - 033, 30
:2 034, 45 2 ?6 034, 44 6
+ 035, 40 :3 035, 45 3
?5 036, 44 5 ³ 036, 36
:3 037, 45 3 ?5 037, 44 5
Forecasting 89
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
:0 038, 45 0 :6 038, 45 6
z 039, 10 g(000 039,43,33,000
:2 040, 45 2 fs
+ 041, 40
?6 042, 44 6
g(000 043,43,33,000
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: α R
1: 1-α R
2: St-1
R3: Tt-1 R
4: Σe2 R
5: Dt R6: D
ˆt+1
R7-R.4: Unused
Program Instructions:
Selecting the "best" smoothing constant (α ):
1. Key in the program and press fCLEARH.
RPN Mode:
2. Key in the number 1 and press \.
3. Key in the "trial " and press ?0-?1.
ALG Mode:
2. Key in the number 1 and press -.
3. Key in the "trial " and press ?0³?1.
4. Key in the first historical value (X1) and press ?2.
5. Key in the second historical value (X2) and press ?6t. The result is the error
between the forecast value D
ˆ
(t+1) and the true value (Xt+1).
6. Press t; the display shows the next forecast D
ˆ
(t+2).
7. Optional: Press :5 to display the smoothed estimate of current demand.
8. Continue steps 5 and 6 for X3, X4, ... Xn until all historical values have been entered.
When doing step 5 merely key in the value and press t (do not press ?6).
9. Press :4. This value represents the cumulative forecasting error (∑e2). Record the
value and the following additional values; press :0 (α), :2 (smoothed average
St-1), :3 (trend Tt-1) and :6 (forecast D
ˆt+1).
10. Press fCLEARH.
11. Repeat steps 2 through 10 until a "best" α is selected based on the lowest cumulative
forecasting error (Register 4).
90 Forecasting
Forecasting:
RPN Mode:
1. Key in the number 1 and press \.
2. Key in the selected α and press ?0-?1.
ALG Mode:
1. Key in the number 1 and press -.
2. Key in the selected α and press ?0³?1.
3. From the selection routine or from a previous forecast:
Key in the smoothed average St-1 and press ?2.
Key in the trend Tt-1 and press ?3.
Key in the forecast D
ˆt+1 and press ?6.
4. Key in the current data value and press t. The output is the error in forecasting the
value just entered.
5. Press t. The displayed value represents the forecast for the next period.
6. Record the following values: :0 (α), :2 (St-1), :3 (Tt-1) and :6 D
ˆ
(t+1) for
use as initial values in the next forecast. You may also wish to record :5 (Dt).
7. Repeat steps 4, 5, and 6 for the next forecast if available.
Example: Select the best smoothing constant based on sales (in thousands of dollars) of
22, 23, 23, 25, 23, 27, 25. Given the current sales in month 8 of 26, forecast the following
month.
Select the smoothing constant (α
):
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH 0.00
1\ 1- 1.00
.5?0- .5?0³ 0.50
?1 ?1 0.50
22?2 22?2 22.00
23?6t 23?6t 0.00
t t 23.00
23tt 23tt 23.25
25tt 25tt 25.25
23tt 23tt 23.69
27tt 27tt 27.13
25tt 25tt 25.95
:4 :4 23.61 Cumulative error (∑e2).
:0 :0 0.50 Smoothing constant (α ).
Forecasting 91
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
:2 :2 25.11 Smoothing average (St-1).
:3 :3 0.42 Trend (Tt-1).
:6 :6 25.95 Last forecast D
ˆ
(t+1).
The procedure is repeated for several
α
's.
Smoothing Constant (α) .5 .1 .25 .2
Cumulative Error (Σe2) 23.61 25.14 17.01 18.03
For the selected α = .25 St+1 = 24.28
Tt-1 = 0.34
D
ˆt+1= 25.64
Forecasting:
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH 0.00
1\ 1- 1.00
.25?0- .25?0³ 0.75
?1 ?1 0.75
24.28?2 24.28?2 24.28
.34?3 .34?3 0.34
25.64?6 25.64?6 25.64
26t 26t 0.36
t t 26.16 Forecast for month 9, ( D
ˆt+1).
:5 :5 25.80 Expected usage for current
(month 8) period, (Smoothed
Dt).
:0 :0 0.25 α
:2
:3
:6
:2
:3
:6
24.71
0.36
26.16
Record for initial values when
month 9 actual figures become
available.
Note: At least 4 periods of current data should be entered before forecasting is attempted.
92
Pricing Calculations
Markup and Margin Calculations
Sales work often involves calculating the various relations between markup, margin,
selling price and costs. Markup is defined as the difference between selling price and cost,
divided by the cost. Margin is defined as the difference between selling price and cost,
divided by selling price. In other words, markup is based on cost and margin is based on
selling price.
The following keystroke sequences are given to readily make these calculations on the
HP 12C Platinum.
CALCULATE GIVEN RPN KEYSTROKES ALG KEYSTROKES
Selling Price Cost & Markup Key in cost, \,
key in markup
(in %), b+.
Key in cost, +,
key in markup
(in %), b³.
Selling Price Cost & Margin Key in cost,
\1\
key in margin (in %),
b-z.
Key in cost,
y-,
key in margin (in %),
b³y.
Cost Selling Price & Markup Key in selling price,
\1\,
key in markup (in %),
b+z.
Key in selling price,
y+,
key in markup (in %),
b³y.
Cost Selling Price & Margin Key in selling price,
\,
key in margin
(in %), b-.
Key in selling price,
-,
key in margin
(in %), b³.
Markup Cost and Selling Price Key in cost, \,
key in selling price,
à.
Key in cost, ³,
key in selling price,
à.
Markup
Margin Key in margin,
\\1
~b-z.
Key in margin,
-y
~b³y.
Margin
Selling Price & Cost Key in selling price,
\, key in cost,
àÞ.
Key in selling price,
³, key in cost,
àÞ.
Margin Markup Key in markup,
\\1
~b+z.
Key in markup,
+y
~b³y.
Pricing Calculations 93
Example 1: If the cost of an item is $160 and the margin is 20%, what is the selling
price? What is the markup?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
160\1\20 160y-20 20. Margin(%).
b-z b³y 200.00 Selling price.
20\\ 20- 20.00 Margin(%)
1~b-z y~b³y 25.00 Markup (%).
Example 2: If an item sells for $21.00 and has a markup of 50%, what is its cost? What is
the margin?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
21\1\50 21y+50 50.00 Markup (%).
b+z b³y 14.00 Cost.
50\\ 50+ 50.00 Markup(%)
1~b+z y~b³y 33.33 Margin (%).
The following HP 12C Platinum program may be helpful for repetitive calculations of
selling price and costs as well as conversions between markup and margin.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
\ 001, 36 ³ 001, 36
g(004 002,43,33,004 g(004 002,43,33,004
Þ 003, 16 Þ 003, 16
1 004, 1 ~ 004, 34
~ 005, 34 + 005, 40
b 006, 25 ~ 006, 34
+ 007, 40 b 007, 25
z 008, 10 ³ 008, 36
t 009, 31 gF 009, 43 40
gF 010, 43 40 g’ 010, 43 20
§ 011, 20 z 011, 10
gF 012, 43 40 ~ 012, 34
§ 013, 20 ³ 013, 36
g(000 014,43,33,000 t 014, 31
fs gF 015, 43 40
g(000 016,43,33,000
fs
94 Pricing Calculations
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0-R.8: Unused
Program Instructions:
1. Key in the program.
2. To calculate selling price, given the markup, key in the cost, press \(³), key in
the markup and press g(000tt.
3. To calculate cost, given the markup, key in the selling price, press \(³), key in
the markup and press g(000t.
4, To calculate selling price, given the margin, key in the cost, press \(³), key in
the margin and press g(003t.
5. To calculate cost, given the margin, key in the selling price, press \(³), key in
the margin and press g(003tt.
RPN Mode:
6. To calculate markup from the margin, key in the margin and press
\g(003t.
7. To calculate margin from the markup, key in the markup and press
\g(000t.
ALG Mode:
6. To calculate markup from the margin, key in the margin and press ³, re-key margin,
g(003t.
7. To calculate margin from the markup, key in the markup and press ³, re-key
markup, g(000t.
Example: Find the cost of an item selling for $38.00 with a margin of 30%. What is the
markup on the item? If the markup is raised to 50%, what will the selling price be?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
38\ 38³ 38.00 Selling price.
30g(003 30g(003 30.00 Margin (%).
tt tt 26.60 Cost.
30\ 30³ 30.00 Margin (%).
g(003t 30g(003t 42.86 Markup (%).
26.6\ 26.6³ 26.60 Cost.
50g(000 50g(000 50.00 New markup.
tt tt 39.90 New selling price.
Pricing Calculations 95
Calculations of List and Net prices With
Discounts
It is often useful to be able to quickly calculate a list or net price when the other price and
a series of discount rates are known. Alternatively, if the list and net price and several
discounts are known it may be desirable to calculate a missing discount. The following
series of keystrokes may be used:
RPN Mode:
1. Key in 1, press \\?1.
2. Key in the first discount (as a percentage) and press b-?§1d.
3. Repeat step 2 for each of the remaining known discount rates.
4. To calculate the list price, key in the net price and press :1z.
5. To calculate the net price, key in the list price and press :1§.
6. To calculate an unknown discount rate, immediately after step 3 (display should show
1.00), key in the net price, press \ and key in the list price.
7. Press :1§z-100§.
ALG Mode:
1. Key in 1, press ?1.
2. Key in 1-, key in the first discount (as a percentage) and press b³?§1.
3. Repeat step 2 for each of the remaining known discount rates.
4. To calculate the list price, key in the net price and press z:1³.
5. To calculate the net price, key in the list price and press §:1³.
6. To calculate an unknown discount rate, immediately after doing step 3 , key in the list
price, press §:1³, then key in the net price.
7. Press àÞ.
Example: The list price of an item is $3.28 and the net price is $1.45. Two of the discount
rates are 48% and 5%. What is the third discount rate?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
1\\ 1
?1 ?1 1.00
48b-?§1 1-48b³?§1 0.52
d 5b-?§11-5b³?§1 0.95
d1.45\
3.28:1 3.28§:1 0.49
§z-100§ ³1.45àÞ 10.51 3rd discount rate (%).
96 Pricing Calculations
The following program for the HP 12C Platinum will be helpful in performing the
calculations:
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
1 001, 1 1 001, 1
~ 002, 34 - 002, 30
b 003, 25 ~ 003, 34
- 004, 30 b 004, 25
?§1 005,44 20 1 ³ 005, 36
g(000 006,43,33,000 ?§1 006,44 20 1
:1 007, 45 1 g(000 007,43,33,000
§ 008, 20 :1 008, 45 1
z 009, 10 § 009, 20
1 010, 1 ~ 010, 34
~ 011, 34 ³ 011, 36
- 012, 30 ~ 012, 34
Æ 013, 26 à 013, 24
2 014, 2 Þ 014, 16
§ 015, 20 g(000 015,43,33,000
g(000 016,43,33,000 fs
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: Unused R1: D’1xD’2... R2-R7: Unused
Program Instructions:
1. Key in the program.
2. Key in 1 and press ?1.
3. Key in the first discount rate (as a percentage) and press t.
4. Repeat step 2 for each of the remaining discount rates.
RPN Mode:
5. To calculate the list price, key in the net price and press :1z.
6. To calculate the net price, key in the list price and press :1§.
7. To calculate the unknown discount rate, key in the net price, press \, key in the list
price and press g(007t.
Pricing Calculations 97
ALG Mode:
5. To calculate the list price, key in the net price and press z:1³.
6. To calculate the net price, key in the list price and press §:1³.
7. To calculate the unknown discount rate, key in the net price, press ³, key in the list
price and press g(008t.
Example: Calculate the unknown discount rate for the previous example. If the list price
is now raised to $3.75 what is the new net price?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
1?1 1?1 1.00
48t 48t 0.52
5t 5t 0.95
1.45\ 1.45³
3.28g(007t3.28g(008t 10.51 3rd discount rate (%).
t t 0.89 Include 3rd discount rate in
calculation.
3.75:1§ 3.75§:1³ 1.66 New net price.
98
Statistics
Curve Fitting
Exponential Curve Fit
Using the ° function of the HP 12C Platinum, a least squares exponential curve fit may
be easily calculated according to the equation y=AeBx. The exponential curve fitting
technique is often used to determine the growth rate of a variable such as a stock's value
over time, when it is suspected that the performance is non-linear. The value for B is the
decimal value of the continuous growth rate. For instance, assume after keying in several
end-of-month price quotes for a particular stock it is determined that the value of B is
0.10. This means that over the measured growth period the stock has experienced a 10%
continuous growth rate.
If B>0, you will have a growth curve. If B<0, you will have a decay curve.
Examples of these are given below.
The procedure is as follows:
1. Press fCLEARH .
2. For each input pair of values, key in the y-value and press g°, key in the
corresponding x-value and press _ .
3. After all data pairs are input, press gR~ to obtain the correlation coefficient
(between ln y and x).
Time
Quantity
GROWTH CURVE
(B>0)
Time
Quantity
DECAY CURVE
(B<0)
Statistics 99
4. Press 1 gRg>0gRg> to obtain A in the equation above.
RPN Mode:
5. Press ~dzg° to obtain B.
6. Press g>1- to obtain the effective growth rate (as a decimal).
ALG Mode:
5. Press z~d³g° to obtain B.
6. Press g>-1³ to obtain the effective growth rate (as a decimal).
7. To make a y-estimate, key in the x-value and press gRg>.
Example 1: A stock's price in history is listed below. What effective growth rate does this
represent? If the stock continues this growth rate, what is the price projected to be at the
end of 2004 (year 7)?
End of Year Price
1998(1) 45
1999(2) 51.5
2000(3) 53.75
2001(4) 80
2002(5) 122.5
2003(6) 210
2004(7) ?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH
45g°1_ 45g°1_ 1.00 First data pair input.
51.5g°2_ 51.5g°2_ 2.00 Second data pair input.
53.75g°3_ 53.75g°3_ 3.00 Third data pair input.
80g°4_ 80g°4_ 4.00 Fourth data pair input.
122.5g°5_ 122.5g°5_ 5.00 Fifth data pair input.
210g°6_ 210g°6_ 6.00 Sixth data pair input.
gR~ gR~ 0.95 Correlation coefficient
(between ln y and x).
1gRg> 1gRg>
0gRg> 0gRg> 27.34 A
~dzg° z~d³g° 0.31 B
g>1- g>-1³ 0.36 Effective growth rate.
7gRg> 7gRg> 232.35 Projected price at end of year
7 (2004).
100 Statistics
For repeated use of this routine, the following HP 12C Platinum program will be useful.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
~ 001, 34 ~ 001, 34
g° 002, 43 23 g° 002, 43 23
~ 003, 34 ~ 003, 34
_ 004, 49 _ 004, 49
g(000 005,43,33,000 g(000 005,43,33,000
gR 006, 43 2 gR 006, 43 2
~ 007, 34 ~ 007, 34
t 008, 31 t 008, 31
1 009, 1 0 009, 0
gR 010, 43 2 gR 010, 43 2
g> 011, 43 22 g> 011, 43 22
0 012, 0 t 012, 31
gR 013, 43 2 1 013, 1
g> 014, 43 22 gR 014, 43 2
t 015, 31 g> 015, 43 22
~ 016, 34 ~ 016, 34
d 017, 33 d 017, 33
z 018, 10 z 018, 10
g° 019, 43 23 ~ 019, 34
t 020, 31 ³ 020, 36
g> 021, 43 22 g° 021, 43 23
1 022, 1 t 022, 31
- 023, 30 g> 023, 43 22
t 024, 31 - 024, 30
gR 025, 43 2 1 025, 1
g> 026, 43 22 ³ 026, 36
g(000 027,43,33,000 t 027, 31
fs gR 028, 43 2
g> 029, 43 22
g(000 030,43,33,000
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: Unused R1: n R
2: Σx
R3: Σx2 R
4: Σy R
5: Σy2 R
6: Σxy
R7-R.6: Unused
Statistics 101
Program Instructions:
1. Key in the program and press fCLEARH.
2. For each input pair of values, key in the y-value and press \(³), key in the
corresponding x- value and press t.
3. After all data pairs are input, press g(006t to obtain the correlation
coefficient (between ln y and x).
4. Press t to obtain A.
5. Press t to obtain B.
6. Press t to obtain the effective growth rate as a decimal.
7. RPN: To make a y-estimate, key in the x-value and press t. For subsequent
estimates, key in the x-value and press g(025t.
7. ALG: To make a y-estimate, key in the x-value and press t. For subsequent
estimates, key in the x-value and press g(028t.
8. For a different set of data, press fCLEARH and go to step 2.
Example 2: Repeat example 1 using the program.
12c platinum /12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH
45\1t 45³1t 1.00 First data pair input.
51.5\2t 51.5³2t 2.00 Second data pair input.
53.75\3t 53.75³3t 3.00 Third data pair input.
80\4t 80³4t 4.00 Fourth data pair input.
122.5\5t 122.5³5t 5.00 Fifth data pair input.
210\6t 210³6t 6.00 Sixth data pair input.
g(006t g(006t 0.95 Correlation coefficient
(between ln y and x).
t t 27.34 A
t t 0.31 B
t t 0.36 Effective growth rate.
7t 7t 232.35 Projected price at the end o
f
year 7 (2004).
102 Statistics
Logarithmic Curve Fit
If your data does not fit a line or an exponential curve, try the following logarithmic curve
fit. This is calculated according to the equation y = A + B (ln x), and all x values must be
positive.
A typical logarithmic curve is shown below.
The procedure is as follows:
1. Press fCLEARH.
2. Key in the first y-value and press \(³). Key in the first x-value and press
g°_. Repeat this step for each data pair.
3. After all data pairs are input, press gR~ to obtain the correlation coefficient
(between y and ln x).
4. Press 1gR0gR to obtain A in the equation above.
5. RPN: Press ~d- to obtain B.
5. ALG: Press -~d³ to obtain B.
6. To make a y-estimate, key in the x-value and press g°gR.
X
Y
Statistics 103
Example 1: A manufacturer observes declining sales of a soon-to-be obsolete product, of
which there were originally 10,000 units in inventory. The cumulative sales figures over a
number of months, given below, may be approximated by a logarithmic curve of the form
y = A + B (ln x), where y represents cumulative sales in units and x the number of months
since the beginning. How many units will be sold by the end of the eighth month?
Month 1 2 3 4 5 6
Cumulative
Sales (units) 1431 3506 5177 6658 7810 8592
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH
1431\ 1431³
1g°_ 1g°_ 1.00 First pair data input.
3506\ 3506³
2g°_ 2g°_ 2.00 Second pair data input.
5177\ 5177³
3g°_ 3g°_ 3.00 Third pair data input.
6658\ 6658³
4g°_ 4g°_ 4.00 Fourth pair data input.
7810\ 7810³
5g°_ 5g°_ 5.00 Fifth pair data input.
8592\ 8592³
6g°_ 6g°_ 6.00 Sixth pair data input.
gR~ gR~ 0.99 Correlation coefficient
(between y and ln x).
1gR0gR 1gR0gR 1,066.15 Value of A.
~d- -~d³ 4,069.93 Value of B.
8g°gR 8g°gR 9,529.34 Total units sold by end of
eighth month.
104 Statistics
Power Curve Fit
Another method of analysis is the power curve or geometric curve. The equation of the
power curve is y = AxB, and the values for A and B are computed by calculations similar to
linear regression. Some examples of power curves are shown below.
The following keystrokes fit a power curve according to the equation ln y = ln A + B(ln x):
1. Press fCLEARH.
2. Key in the first y-value and press g°. Key in the first x-value and press
g°_. Repeat this step for all data pairs.
3. Press gR~, to obtain the correlation coefficient (between ln y and ln x).
4. Press 0gRg> to obtain A in the above equation.
5. RPN: Press 1gR0gR~d- to obtain B.
5. ALG: Press 1gR0gR-~d³ to obtain B.
6. To make a y-estimate, key in the x-value and press g°gRg>.
Example: If Galileo had wished to investigate quantitatively the relationship between the
time (t) for a falling object to hit the ground and the height (h) it has fallen, he might have
released a rock from various levels of the Tower of Pisa (which was leaning even then)
and timed its descent by counting his pulse. The following data are measurements Galileo
might have made.
t (pulses) 2 2.5 3.5 4 4.5
h (feet) 30 50 90 130 150
B
> 1
0 < B <1
X
Y
0
B < 0
X
Y
0
Statistics 105
Find the power curve formulas that best expresses h as a function of t (h = AtB).
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH
30g° 30g°
2g°_ 2g°_ 1.00 First pair data input.
50g° 50g°
2.5g°_ 2.5g°_ 2.00 Second pair data input.
90g° 90g°
3.5g°_ 3.5g°_ 3.00 Third pair data input.
130g° 130g°
4g°_ 4g°_ 4.00 Fourth pair data input.
150g° 150g°
4.5g°_ 4.5g°_ 5.00 Fifth pair data input.
gR~ gR~ 1.00 Correlation coefficient
(between In y and ln x).
0gRg> 0gRg> 7.72 Value of A.
1gR0gR 1gR0gR
~d- -~d³ 1.99 Value of B.
The formula that best expresses h as a function of t is
99.1
72.7 th =
We know, as Galileo did not, that in fact h is proportional to t2.
Standard Error of the Mean
The standard error of the mean is a measure of how reliable the mean of a sample (X) is
as an estimator of the mean of the population from which the sample was drawn.
To calculate the standard error of the mean:
1. Press fCLEARH.
2. If you are summing one set of numbers, key in the first number and press _.
Continue until you have entered all of the values.
3. If you are summing two sets of numbers, key in the y-value and press \(³), key
in the x-value and press _. Continue until you have entered all of the values.
4. Press gÖ to obtain the mean of the x-values.
RPN Mode:
5. Press gv:1grz to obtain the standard error of the mean of the x-values.
6. Alternatively, press gv~:1grz to obtain the standard error for the
mean of the y-values.
106 Statistics
ALG Mode:
5. Press gvz:1gr³ to obtain the standard error of the mean of the x-
values.
6. Alternatively, press gv~z:1gr³ to obtain the standard error for the
mean of the y-values.
Example: A sample of 6 one-bedroom apartment rentals reveals that one rents for $190
per month unfurnished, one rents for $200 per month, two rent for $205 per month, one
rents for $216 per month, and one rents for $220 per month. What are the mean monthly
rental and the standard deviation? What is the standard error of the mean?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH
190_200_ 190_200_
205_205_ 205_205_
216_220_ 216_220_ 6.00 Total number of inputs.
gÖ gÖ 206.00 Average monthly rent.
gv gv 10.86 Standard deviation.
:1grz z:1gr³ 4.43 Standard error of the mean.
Mean, Standard Deviation, Standard Error for
Grouped Data
Grouped data are presented in frequency distributions to save time and effort in writing
down (or entering) each observation individually. Given a set of data points
x1, x2, ... , xn
with respective frequencies
f1, f2, ... , fn
this procedure computes the mean, standard deviation, and standard error of the mean.
1. Press fCLEARH.
RPN Mode:
2. Key in the first value and press \\.
3. Key in the respective frequency and press ?+0§_. The display shows the
number of data points entered.
ALG Mode:
2. Key in the first value and press ³.
3. Key in the respective frequency and press ?+0§~³gF~_. The
display shows the number of data points entered.
4. Repeat steps 2 and 3 for each data point.
Statistics 107
5. To calculate the mean (average) press :0?1:6?3gÖ.
6. Press gv to find the standard deviation.
7. RPN: Press :0grz to find the standard error of the mean.
7. ALG: Press z:0gr³ to find the standard error of the mean.
Example 1: A survey of 266 one-bedroom apartment rentals reveals that 54 rent for $190
a month unfurnished, 32 rent for $195 per month, 88 rent for $200 per month, and 92 rent
for 206 per month. What are the average monthly rental, the standard deviation, and the
standard error of the mean?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH
190\\ 190³54?+0
54?+0§_ §~³gF~_ 1.00 First data pair entered.
195\\ 195³32?+0
32?+0§_ §~³gF~_ 2.00 Second data pair entered.
200\\ 200³88?+0
88?+0§_ §~³gF~_ 3.00 Third data pair entered.
206\\ 206³92?+0
92?+0§_ §~³gF~_ 4.00 Fourth data pair entered.
:0?1:6 :0?1:6
?3gÖ ?3gÖ 199.44 Average monthly rent.
gv gv 5.97 Standard deviation.
:0grz z:0gr³ 0.37 Standard error of the
mean.
Use the following HP 12C Platinum program for the previous example:
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
?+0 001,44 40 0 ?+0 001,44 40 0
§ 002, 20 § 002, 20
_ 003, 49 ~ 003, 34
g(000 004,43,33,000 ³ 004, 36
:0 005, 45 0 gF 005, 43 40
?1 006, 44 1 ~ 006, 34
:6 007, 45 6 _ 007, 49
?3 008, 44 3 g(000 008,43,33,000
gÖ 009, 43 0 :0 009, 45 0
t 010, 31 ?1 010, 44 1
108 Statistics
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
gv 011, 43 48 :6 011, 45 6
t 012, 31 ?3 012, 44 3
:0 013, 45 0 gÖ 013, 43 0
gr 014, 43 21 t 014, 31
z 015, 10 gv 015, 43 48
g(000 016,43,33,000 t 016, 31
fs z 017, 10
:0 018, 45 0
gr 019, 43 21
³ 020, 36
g(000 021,43,33,000
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: Σfi R
1: Σfi R
2: Σfixi
R3: Σfixi
2 R
4: Σxi R
5: Σxi
2 R
6: Σfixi
2
R7-R.7: Unused
Program Instructions:
1. Key in the program.
2. Press fCLEARH.
3. RPN: Key in the first value and press \\.
3. ALG: Key in the first value and press ³.
4. Key in the respective frequency and press t. The display shows the number of data
points entered.
5. Repeat steps 3 and 4 for each data point.
6. RPN: To calculate the mean, press g(005t.
6. ALG: To calculate the mean, press g(009t.
7. Press t to find the standard deviation.
8. Press t to find the standard error of the mean.
9. For a new case, go to step 2.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH
190\\ 190³
54t 54t 1.00 First data pair.
Statistics 109
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
195\\ 195³
32t 32t 2.00 Second data pair.
200\\ 200³
88t 88t 3.00 Third data pair.
206\\ 206³
92t 92t 4.00 Total number of data sets.
g(005t g(009t 199.44 Average monthly rent (mean).
t t 5.97 Standard deviation.
t t 0.37 Standard error of the mean.
Chi-Square Statistics
The chi-square statistic is a measure of the goodness of fit between two sets of
frequencies. It is used to test whether a set of observed frequencies differs from a set of
expected frequencies sufficiently to reject the hypothesis under which the expected
frequencies were obtained.
In other words, you are testing whether discrepancies between the observed frequencies
(Oi) and the expected frequencies (Ei) are significant, or whether they may reasonable be
attributed to chance. The formula generally used is:
(
)
∑
=
−
=n
ii
ii
E
EO
1
2
2
χ
If there is a close agreement between the observed and expected frequencies, χ2 will be
small. If the agreement is poor, χ2 will be large.
The following keystrokes calculate the χ2 statistic:
1. Press fCLEARH .
RPN Mode:
2. Key in the first Oi value and press \ .
3. Key in the first Ei value and press ?0-\§:0z+ .
ALG Mode:
2. Key in the first Oi value and press - .
3. Key in the first Ei value and press ?0³g’z:0+~³.
4. Repeat steps 2 and 3 for all data pairs. The χ2 value is displayed.
110 Statistics
Example 1: A suspect die from a Las Vegas casino is brought to an independent testing
firm to determine its bias, if any. The die is tossed 120 times and the following results
obtained.
Number 1 2 3 4 5 6
Observed Frequency 25 17 15 23 24 16
The expected frequency = 120 throws / 6 sides, or E = 20 for each number, 1 thru 6.
(Since E is a constant in this example, there is no need to store it in R0 each time.)
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH
25\ 25-
20?0-\ 20?0³g’
§:0z+ z:0+~³ 1.25
17\20- 17-20³g’
\§:0z+ z:0+~³ 1.70
15\20- 15-20³g’
\§:0z+ z:0+~³ 2.95
23\20- 23-20³g’
\§:0z+ z:0+~³ 3.40
24\20- 24-20³g’
\§:0z+ z:0+~³ 4.20
16\20- 16-20³g’
\§:0z+ z:0+~³ 5.00 χ2
The number of degrees of freedom is (n-1). Since n = 6, the degrees of freedom = 5.
Consulting statistical tables, you look up χ2 to a 0.05 significance level with 5 degrees of
freedom, and see that χ20.05,5 = 11.07. Since χ2 = 5 is within 11.07, we may conclude that
to a 0.05 significance level (probability = .95), the die is fair.
Try the following HP 12C Platinum program with the same example.
Statistics 111
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
?0 001, 44 0 ~ 001, 34
- 002, 30 à 002, 24
\ 003, 36 b 003, 25
§ 004, 20 g’ 004, 43 20
:0 005, 45 0 § 005, 20
z 006, 10 ~ 006, 34
+ 007, 40 + 007, 40
g(000 008,43,33,000 ~ 008, 34
fs ³ 009, 36
g(000 010,43,33,000
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: Ei R
1-R.9: Unused
Program Instructions:
1. Key in the program.
2. Press fCLEARH.
3. Key in the first Oi value and press \(³).
4. Key in the first Ei value and press t.
5. Repeat steps 3 and 4 for all data pairs. The χ2 value is displayed.
6. For a new case, go to step 2.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH
25\ 25³
20t 20t 1.25
17\ 17³
20t 20t 1.70
15\ 15³
20t 20t 2.95
23\ 23³
20t 20t 3.40
24\ 24³
20t 20t 4.20
16\ 16³
20t 20t 5.00 χ2
112 Statistics
Normal Distribution
The normal (or Gaussian) distribution is an important tool in statistics and business
analysis. The following HP 12C Platinum program gives an approximation to the upper
tail area Q under a standardized normal distribution curve, given x. The upper tail area
signifies the probability of occurrence of all values ≥
x.
(
)
+
++
−≅ 165/703
56235183
2
1
)( x
x
EXPxQ
Relative error less than 0.042% over the range 0 < x < 5.5
Reference:
Stephen E. Derenzo, "Approximations for Hand Calculators Using Small Integer
Coefficients," Mathematics of Computation, Vol. 31, No. 137, page 2014,225; Jan 1977.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
?0 001, 44 0 ?0 001, 44 0
8 002, 8 7 002, 7
3 003, 3 0 003, 0
§ 004, 20 3 004, 3
3 005, 3 z 005, 10
5 006, 5 ~ 006, 34
1 007, 1 + 007, 40
x
f(x)
Q
(
x
)
0
Statistics 113
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
+ 008, 40 1 008, 1
:0 009, 45 0 6 009, 6
§ 010, 20 5 010, 5
5 011, 5 ³ 011, 36
6 012, 6 :0 012, 45 0
2 013, 2 § 013, 20
+ 014, 40 8 014, 8
7 015, 7 3 015, 3
0 016, 0 + 016, 40
3 017, 3 3 017, 3
:0 018, 45 0 5 018, 5
z 019, 10 1 019, 1
1 020, 1 § 020, 20
6 021, 6 :0 021, 45 0
5 022, 5 + 022, 40
+ 023, 40 5 023, 5
z 024, 10 6 024, 6
Þ 025, 16 2 025, 2
g> 026, 43 22 z 026, 10
2 027, 2 ~ 027, 34
z 028, 10 ³ 028, 36
g(000 029,43,33,000 g> 029, 43 22
fs + 030, 40
³ 031, 36
y 032, 22
g(000 033,43,33,000
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: x R
1-R.6: Unused
Program Instructions:
1. Key in the program.
2. Key in x and press t to compute Q(x).
3. Repeat step 2 for each new case.
Example: Find Q(x) for x = 1.18 and x = 2.1.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
1.18t 1.18t 0.12 Q(1.18)
2.1t 2.1t 0.02 Q(2.1)
114 Statistics
Covariance
Covariance is a measure of the interdependence between paired variables (x and y). Like
standard deviation, covariance may be defined for either a sample (Sxy) or a population
(S'xy) as follows:
Sxy = r · sx · sy
S'xy = r · s'x · s'y
The following procedure finds the covariance of a sample (Sxy) and of a population (S'xy):
1. Press fCLEARH.
2. Key in the y-values and press \(³).
3. Key in the x-values and press _.
4. Repeat steps 2 and 3 for all data pairs.
RPN Mode:
5. Press gv§\gRd§ to obtain the value of Sxy.
6. Press :1 1-:1z§ to obtain S'xy.
ALG Mode:
5. Press gv1gRd§~§~³ to obtain the value of Sxy.
6. Press 1-:1y§~³ to obtain S'xy.
Example 1: Find the sample covariance (Sxy) and population covariance (S'xy) for the
following paired variables:
xi 26 30 44 50 62 68 74
yi 92 85 78 81 54 51 40
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH
92\26_ 92³26_
85\30_ 85³30_
78\44_ 78³44_
81\50_ 81³50_
54\62_ 54³62_
51\68_ 51³68_
40\74_ 40³74_ 7.00 Total number of entries.
gv§\ gv1
gR gRd§
d§ ~§~³ -354.14 Sxy
:1 1-:1 1-:1y
z§ §~³ -303.55 S'xy
Statistics 115
Try the previous example using the following HP 12C Platinum program:
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
_ 001, 49 _ 001, 49
g(000 002,43,33,000 g(000 002,43,33,000
gv 003, 43 48 gv 003, 43 48
§ 004, 20 1 004, 1
\ 005, 36 gR 005, 43 2
gR 006, 43 2 d 006, 33
d 007, 33 § 007, 20
§ 008, 20 ~ 008, 34
t 009, 31 § 009, 20
:1 010, 45 1 ~ 010, 34
1 011, 1 ³ 011, 36
- 012, 30 t 012, 31
: 013, 45 1 1 013, 1
z 014, 10 - 014, 30
§ 015, 20 :1 015, 45 1
g(000 016,43,33,000 y 016, 22
fs § 017, 20
~ 018, 34
³ 019, 36
g(000 020,43,33,000
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: Unused R1: n R2: Σx
R3: Σx2 R
4: Σy R
5: Σy2 R
6: Σxy
R7-R.7: Unused
Program Instructions:
1. Key in the program.
2. Press fCLEARH.
3. Key in the y-value and press \(³).
4. Key in the x-value and press t. Repeat steps 3 and 4 for all data pairs.
5. Press g(003t to obtain the value of Sxy.
6. Press t to obtain S'xy.
7. For a new case, go to step 2.
116 Statistics
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH
92\26t 92³26t
85\30t 85³30t
78\44t 78³44t
81\50t 81³50t
54\62t 54³62t
51\68t 51³68t
40\74t 40³74t 7.00 Total number of entries.
g(003t g(003t -354.14 Sxy
t t -303.55 S'xy
Permutations
A permutation is an ordered subset of a set of distinct objects. The number of possible
permutations, each containing n objects, that can be formed from a collection of m distinct
objects is given by:
)!(
!
nm
m
P
nm −
=
where m, n are integers and 69 ≥
m ≥
n ≥
0.
Use the following HP 12C Platinum program to calculate the number of possible
permutations.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
?0 001, 44 0 gF 001, 43 40
~ 002, 34 - 002, 30
ge 003, 43 3 ~ 003, 34
gF 004, 43 40 ³ 004, 36
:0 005, 45 0 ~ 005, 34
- 006, 30 ge 006, 43 3
ge 007, 43 3 z 007, 10
z 008, 10 ~ 008, 34
g(000 009,43,33,000 ge 009, 43 3
fs ³ 010, 36
g(000 011,43,33,000
fs
Statistics 117
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: n R
1-R.8: Unused
Program Instructions:
1. Key in the program.
2. Key in m and press \(³).
3. Key in n and press t to calculate mPn.
4. For a new case go to step 2.
Example: How many ways can 10 people be seated on a bench if only 4 seats are
available?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
10\ 10³
4t 4t 5,040.00 10P4.
Combinations
A combination is a selection of one or more of a set of distinct objects without regard to
order. The number of possible combinations, each containing n objects, that can be
formed from a collection of m distinct objects is given by:
()
!!
!
nnm
m
Cnm −
=
Where m, n are integers and 69 ≥
m ≥
n ≥
0.
Use the following HP 12C Platinum to calculate the number of possible combinations.
118 Statistics
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
?0 001, 44 0 gF 001, 43 40
~ 002, 34 - 002, 30
ge 003, 43 3 ~ 003, 34
gF 004, 43 40 ³ 004, 36
:0 005, 45 0 ~ 005, 34
- 006, 30 ge 006, 43 3
ge 007, 43 3 z 007, 10
:0 008, 45 0 ~ 008, 34
ge 009, 43 3 ge 009, 43 3
§ 010, 20 z 010, 10
z 011, 10 gF 011, 43 40
g(000 012,43,33,000 ge 012, 43 3
fs ³ 013, 36
g(000 014,43,33,000
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: n R
1-R.8: Unused
Program Instructions:
1. Key in the program.
2. Key in m and press \(³).
3. Key in n and press t to calculate mCn.
4. For a new case, go to step 2.
Example: A manager wants to choose a committee of three people from the seven
engineers working for him. In how many different ways can the committee be selected?
12c platinum / 12C
RPN Keystrokes
12c platinum
ALG
Keystrokes Display Comments
7\ 7³
3t 3t 35.00 7C3.
Statistics 119
Random Number Generator
This HP 12C Platinum program calculates uniformly distributed pseudo-random numbers
ui in the range
0 < ui < 1
The following method is used:
• ui+1 = fractional part of (997 ui)
• where i = 0, 1, 2, ...
• u0 = 0.5284163* (seed)
The period of this generator has a length of 500,000 numbers and the generator passes the
frequency test (chi square) for uniformity, the serial test and the run test. The most
significant digits (the left hand digits) are the most random digits. The right most digits
are significantly less random.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
. 001, 48 . 001, 48
5 002, 5 5 002, 5
2 003, 2 2 003, 2
8 004, 8 8 004, 8
4 005, 4 4 005, 4
1 006, 1 1 006, 1
6 007, 6 6 007, 6
3 008, 3 3 008, 3
?0 009, 44 0 § 009, 20
9 010, 9 9 010, 9
9 011, 9 9 011, 9
7 012, 7 7 012, 7
§ 013, 20 ³ 013, 36
gT 014, 43 24 gT 014, 43 24
?0 015, 44 0 ?0 015, 44 0
t 016, 31 t 016, 31
g(010 017,43,33,010 g(009 017,43,33,009
fs fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: Ui R
1-R.7: Unused
*Other seeds may be selected but the quotient of (seed x 107) divided by two or five must not be an
integer. Also, it would be wise to statistically test other seeds before using them.
120 Statistics
Program Instructions:
1. Key in the program.
2. To generate a random number, press t.
3. Repeat step 2 as many times as desired.
Example: Generate a sequence of 5 random numbers.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
t t 0.83 Random number.
t t 0.56
t t 0.27
t t 0.04
t t 0.20
121
Personal Finance
Homeowners Monthly Payment Estimator
It is often useful, when comparison shopping for a mortgage or determining the
appropriate price range of houses to consider, to be able to quickly estimate the monthly
payment given the purchase price, tax rate per $1000, percent down, interest rate and term
of the loan.
The calculation assumes that the assessed value is 100% of the sales price and does not
take into account financing of the closing costs.
A simple keystroke procedure may be used to calculate the monthly payment:
1. Press g and press fCLEARG.
2. Key in the annual interest rate and press gC.
3. Key in the term of the loan (in years) and press gA.
4. Key in the purchase prices and press ?1.
RPN Mode:
5. Key in the percent down and press b-$.
6. Key in the tax rate in dollars per thousand and press
:1§12000zÞ\PP+ .
(A negative sign is the convention for cash paid out).
ALG Mode:
5. Press -, key in the percent down and press
b$P:1§.
6. Key in the tax rate in dollars per thousand and press
Þz12000+~³.
(A negative sign is the convention for cash paid out).
Example: What would your monthly payments be on a $65,000 house in a neighborhood
with a $25 per thousand tax rate and a 10 ¾ % interest rate on a 35 year loan with 10%
down?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
g gÂ
fCLEARG fCLEARG
10.75gC 10.75gC 0.90 Monthly interest rate.
35gA 35gA 420.00 Months of loan.
65000?1 65000?1 65,000.00 Purchase price.
122 Personal Finance
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
10b-$ -10b$ 58,500.00 Mortgage balance.
25:1§ P:1§
12000zÞ 25Þz12000+-135.42 Approximate monthly taxes.
\PP ~
+ ³ -672.16 Approximate monthly
payment.
The following HP 12C Platinum program may be used instead of the above.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
g 001, 43 8 g 001, 43 8
:1 002, 45 1 :1 002, 45 1
:2 003, 45 2 - 003, 30
b 004, 25 :2 004, 45 2
- 005, 30 b 005, 25
$ 006, 13 $ 006, 13
\ 007, 36 P 007, 14
gF 008, 43 40 :1 008, 45 1
+ 009, 40 § 009, 20
:3 010, 45 3 :3 010, 45 3
§ 011, 20 z 011, 10
1 012, 1 1 012, 1
2 013, 2 2 013, 2
Æ 014, 26 Æ 014, 26
3 015, 3 3 015, 3
z 016, 10 - 016, 30
Þ 017, 16 ~ 017, 34
\ 018, 36 ~ 018, 34
P 019, 14 ³ 019, 36
P 020, 14 g(000 020,43,33,000
+ 021, 40 fs
g(000 022,43,33,000
fs
REGISTERS
n: Term i: Interest PV: Loan PMT: Loan PMT
FV: 0 R0: Unused R1: Purch. Price R2: % Down
R3: Tax rate R4-R.7: Unused
Personal Finance 123
Program Instructions:
1. Key in the program.
2. Press fCLEARG.
3. Key in the annual interest rate and press gC .
4. Key in the term of the loan in years and press gA .
5. Key in the purchase price and press ?1.
6. Key in the percent down and press ?2.
7. Key in the tax rate in dollars per thousand and press ?3.
8. To calculate the approximate monthly payment, press t.
9. For a new case, store only the new variables by performing steps 3 thru 7 as needed.
Press t for the new approximate monthly payment.
Example: Solve the previous example using the HP 12C Platinum program.
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARG fCLEARG
10.75gC 10.75gC 0.90 Monthly interest.
35gA 35gA 420.00 Months of loan.
65000?1 65000?1 65,000.00 Purchase price.
10?2 10?2 10.00 Percent down.
25?3 25?3 25.00 Tax rate per thousand.
t t -672.16 Approximate monthly
payment.
What would the approximate payment be if the loan was at 10% interest?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
10gCt 10gCt -638.33 Approximate monthly
payment.
What if the down payment is increased to 20%?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
20?2t 20?2t -582.45 Approximate monthly
payment.
124 Personal Finance
Tax-Free Individual Retirement (IRA) or
Keogh Plan
The advent of tax-free retirement accounts (IRA or Keogh) has resulted in considerable
benefits for many persons who are not able to participate in group profit sharing or
retirement plans. The savings due to the tax-free status are often considerable, but
complex to calculate. Required data are: the years to retirement, the total annual
investment, the compound annual interest rate of the investment, and an assumed tax rate
(the dividend tax rate) which would be paid on a similar but taxable investment. This
program calculates:
1. The future cash value of the tax-free investment (the dividend tax rate does not apply).
2. The total cash paid in.
3. The total dividends paid (the tax-free status means these dividends are tax-free).
4. The future value of the investment at retirement, assuming that after retirement you
make withdrawals at a rate which causes the money to be taxed at the withdrawal tax
rate. This rate is often assumed to be one half of the dividend tax rate.
5. The diminished purchasing power assuming a given annual inflation rate.
6. The future value of a comparable taxable investment (the dividend tax rate applies).
7. The diminished purchasing power of a comparable taxable investment.
Notes:
• The calculations run from the beginning of the first year to the end of the last
year.
• The interest (annual yield), i, should be entered to as many significant figures as
possible for maximum accuracy.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
:n 001, 45 11 :n 001, 45 11
:P 002, 45 14 § 002, 20
§ 003, 20 :P 003, 45 14
t 004, 31 + 004, 40
+ 005, 40 t 005, 31
t 006, 31 ~ 006, 34
:M 007, 45 15 ³ 007, 36
:2 008, 45 2 t 008, 31
b 009, 25 :M 009, 45 15
- 010, 30 - 010, 30
t 011, 31 :2 011, 45 2
1 012, 1 b 012, 25
Personal Finance 125
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
:3 013, 45 3 ³ 013, 36
b 014, 25 t 014, 31
+ 015, 40 1 015, 1
:n 016, 45 11 + 016, 40
q 017, 21 :3 017, 45 3
z 018, 10 b 018, 25
t 019, 31 ³ 019, 36
:¼ 020, 45 12 q 020, 21
:1 021, 45 1 :n 021, 45 11
b 022, 25 z 022, 10
- 023, 30 ~ 023, 34
¼ 024, 12 ~ 024, 34
M 025, 15 ³ 025, 36
t 026, 31 t 026, 31
g(012 027,43,33,012 :¼ 027, 45 12
fs - 028, 30
:1 029, 45 1
b 030, 25
¼ 031, 12
M 032, 15
t 033, 31
g(015 034,43,33,015
fs
REGISTERS
n: Years i: Used PV: 0 PMT: Yearly Pmt
FV: Used R0: Unused R1: Dividend Tax % R2: Withdrawal Tax %
R3: Inflation % R4-R.5: Unused
Program Instructions:
1. Key in the program.
2. Press fCLEARH and press g× .
3. Key in the dividend tax rate as a percentage and press ?1.
3. Key in the withdrawal tax rate as a percentage and press ?2.
3. Key in the inflation rate as a percentage and press ?3.
6. Key in years to retirement and press n.
7. Key in the interest rates as a percentage and press ¼.
8. Key in the annual payment and press ÞP.
9. Press M to calculate the future value of the tax free investment.
10. Press t to compute the total cash paid in.
126 Personal Finance
11. Press t to compute the total dividends paid.
12. Press t to compute the future value when, after retirement, money is withdrawn at
a rate causing the tax rate to equal ½ the rate paid during the pay in period.
13. Press t to compute the diminished purchasing power, in terms of today's dollars,
of the future value assuming a 10% annual inflation rate.
14. Press t to compute the future value of an ordinary tax investment.
15. Press t to compute the diminished purchasing power of the ordinary tax
investment.
Example: Assuming a 35 year investment period with a dividend rate of 8.175% and an
income tax rate of 40%:
1. If you invest $1500 each year in a tax free account, what will its value be at
retirement?
2. How much cash will be paid in?
3. What will be the value of the earned dividends?
4. After retirement, if you withdraw cash form the account at a rate such that it will be
taxed at a rate equal to one-half the rate paid during the pay-in period, what will be
the after-tax value?
5. What is the diminished purchasing power of that amount, in today's dollars, assuming
10% annual inflation?
6. If you invest the same amount ($1500 after taxes for a non-Keogh or non-IRA
account) each year with dividends taxed as ordinary income, what will be the total
tax-paid cash at retirement?
7. What is the purchasing power of that figure in terms of today's dollars?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH
g× g×
40?1 40?1 40.00 Dividend tax rate.
20?2 20?2 20.00 Withdrawal tax rate.
10?3 10?3 10.00 Inflation rate.
35n 35n 35.00 Years to retirement.
8.175¼ 8.175¼ 8.18 Dividend rate.
1500ÞP 1500ÞP -1,500.00 Annual payment.
M M 290,730.34 Future value at retirement.
t t -52,500.00 Cash paid in.
t t 238,230.34 Earned dividends (untaxed).
t t 232,584.27 After-tax value.
t t 8,276.30 Diminished purchasing power.
t t 139,360.09 Tax-paid cash at retirement.
t t 4,959.00 Purchasing power of tax-paid
cash at retirement.
Personal Finance 127
Stock Portfolio Evaluation and Analysis
This program evaluates a portfolio of stocks given the current market price per share and
the annual dividend. The user inputs the initial purchase price of a stock, the number of
shares, the beta coefficient*, the annual dividend, and the current market price for a
portfolio of any size.
The program returns the percent change in value of each stock and the valuation and beta
coefficient* of the entire portfolio. Output includes the original portfolio value, the new
portfolio value, the percent change in the value and the annual dividend and yield as a
percent of the current market value. The overall beta coefficient of the portfolio is also
calculated.
Note:
The beta coefficient analysis is optional. Key in 1.00 if beta is not to be analyzed.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
:4 001, 45 4 ?6 001, 44 6
gm 002, 43 35 :4 002, 45 4
g(021 003,43,33,021 gm 003, 43 35
?-4 004,44 30 4 g(026 004,43,33,026
§ 005, 20 ?-4 005,44 30 4
:7 006, 45 7 d 006, 33
§ 007, 20 § 007, 20
?+0 008,44 40 0 :7 008, 45 7
~ 009, 34 ³ 009, 36
:7 010, 45 7 ?+0 010,44 40 0
§ 011, 20 ~ 011, 34
?+1 012,44 40 1 § 012, 20
d 013, 33 :7 013, 45 7
§ 014, 20 ³ 014, 36
?+3 015,44 40 3 ?+1 015,44 40 1
:5 016, 45 5 d 016, 33
gF 017, 43 40 § 017, 20
à 018, 24 ~ 018, 34
t 019, 31 ³ 019, 36
* The beta coefficient is a measure of a stock variability (risk) compared to the market in general.
Beta values for individual stocks can be acquired from brokers, investment publications or the local
business library.
128 Personal Finance
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
g(001 020,43,33,001 ?+3 020,44 40 3
+ 021, 40 :5 021, 45 5
~ 022, 34 :6 022, 45 6
?7 023, 44 7 à 023, 24
§ 024, 20 t 024, 31
?5 025, 44 5 g(001 025,43,33,001
?+2 026,44 40 2 d 026, 33
1 027, 1 ?5 027, 44 5
?4 028, 44 4 § 028, 20
t 029, 31 ~ 029, 34
g(001 030,43,33,001 ?7 030, 44 7
:2 031, 45 2 ³ 031, 36
t 032, 31 ?+2 032,44 40 2
:0 033, 45 0 1 033, 1
t 034, 31 ?4 034, 44 4
à 035, 24 t 035, 31
t 036, 31 g(001 036,43,33,001
:0 037, 45 0 :2 037, 45 2
:1 038, 45 1 t 038, 31
t 039, 31 :0 039, 45 0
Z 040, 23 t 040, 31
t 041, 31 à 041, 24
:3 042, 45 3 t 042, 31
:0 043, 45 0 :0 043, 45 0
z 044, 10 :1 044, 45 1
g(000 045,43,33,000 t 045, 31
fs Z 046, 23
t 047, 31
:3 048, 45 3
z 049, 10
:0 050, 45 0
³ 051, 36
g(000 052,43,33,000
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: ΣPV R
1: ΣDIV R
2: ΣOrig. Val.
R3: ΣPiSiβi R
4: Flag R5: Pi ni R
6: Pi
R7: Si R
8-R.1: Unused
Personal Finance 129
Program Instructions:
1. Key in the program.
2. Initialize the program by pressing fCLEARH.
3. Key in the number of shares of a stock and press \(³).
4. Key in the initial purchase of the stock and press t.
5. Key in the beta coefficient of the stock and press \(³).
6. Key in the annual dividend of the stock and press \(³).
7. Key in the present price of the stock and press t. The display will show the
percent change in the stock value.
8. Repeat steps 3 through 7 until all the stocks are entered.
9. Next, to evaluate the entire portfolio, press :
RPN: g(031
ALG: g(037
10. Press t to see the initial portfolio value.
11. Press t to see the present portfolio value.
12. Press t to see the percent change in value.
13. Press t to see the total yearly dividend.
14. Press t to see the annual dividend yield as a percent of the current market value.
15. Press t to see the beta coefficient of the portfolio.
16. For a new case return to step 2.
Example: Evaluate the following portfolio:
Number of
Shares Held Initial
Purchase
Price
Beta
Coefficient Annual
Dividend Present
Market Price Stock
100 25.63 .8 $1.70 27.25 Int'l Heartburn
200 30.25 1.2 $2.10 33.50 P. D. Q.
50 89.88 1.3 $4.55 96.13 Datacrunch
500 65.25 .6 $3.50 64.38 N.W. Sundial
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH 0.00 Int'l Heartburn
100\ 100³ 100.00
25.63t 25.63t 1.00
.8\ .8³ 0.80
1.70\ 1.70³ 1.70
27.25t 27.25t 6.32 Percent change in Stock's
value.
130 Personal Finance
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
200\ 200³ 200.00 P. D. Q.
30.25t 30.25t 1.00
1.2\ 1.2³ 1.20
2.10\ 2.10³ 2.10
33.5t 33.5t 10.74 Percent change in Stock's
value.
50\ 50³ 50.00 Datacrunch
89.88t 89.88t 1.00
1.3\ 1.3³ 1.30
4.55\ 4.55³ 4.55
96.13t 96.13t 6.95 Percent change in Stock's
value.
500\ 500³ 500.00 N. W. Sundial
65.25t 65.25t 1.00
.6\ .6³ 0.60
3.50\ 3.50³ 3.50
64.38t 64.38t -1.33 Percent change in Stock's
value.
g(031 g(037
t t 45,732.00 Original value.
t t 46,421.50 Present value.
t t 1.51 Percent change in value.
t t 2,567.50 Total yearly dividend.
t t 5.53 Annual dividend yield.
t t 0.77 Portfolio beta coefficient.
131
Canadian Mortgages
In Canada, interest is compounded semi-annually with payments made monthly. This
results in a different monthly mortgage factor than is used in the United States and
preprogrammed into the HP 12C Platinum. This difference can be easily handled by the
addition of a few keystrokes. For any problem requiring an input for ¼, the Canadian
mortgage factor is calculated first and then this value is entered in for ¼ in the
calculation to give the answer for Canada.
The keystrokes to calculate the monthly Canadian mortgage factor are:
RPN Mode:
1. Press fCLEARGgÂ.
2. Key in 6 and press n.
3. Key in 200 and press \$.
4. Key in the annual interest rate as a percentage and press +ÞM.
5. Press ¼.
ALG Mode:
1. Press fCLEARGgÂ.
2. Key in 2 and press n.
3. Key in the annual interest rate as a percentage and press z2¼.
4. Key in 1 and press $M.
5. Press 12n¼.
The Canadian mortgage factor is now stored in ¼ for future use. The examples below
show how this factor is used for ¼ in Canadian mortgage problems. Example 3 shows
how to reverse this procedure and obtain the annual Canadian interest rate from the
monthly Canadian mortgage factor.
Periodic Payment Amount
Example 1: What is the monthly payment required to fully amortize a 30-year, $30,000
Canadian mortgage if the interest rate is 9%?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARG fCLEARG
g gÂ
6n200\$ 2n9z2¼
9+ÞM¼ 1$M12n¼ 0.74 Canadian mortgage factor.
30gA 30gA 360.00 Total monthly periods in
mortgage life.
30000$0M 30000$0M
P P -237.85 Monthly payment.
132 Canadian Mortgages
Number of Periodic Payments to Fully
Amortize a Mortgage
Example 2: An investor can afford to pay $440 per month on a $56,000 Canadian
mortgage. If the annual interest rate is 9 ¼ %, how long will it take to completely
amortize this mortgage?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARG fCLEARG
g gÂ
6n200\$ 2n9.25z2¼
9.25+ÞM¼ 1$M12n¼ 0.76 Canadian mortgage factor.
440ÞP 440ÞP -440.00 Monthly payment.
56000$0Mn 56000$0Mn 437.00 Total number of monthly
payments.
Effective Interest Rate (Yield)
Example 3: A Canadian mortgage has monthly payments of $612.77 with a maturity of
25 years. The principal amount is $75,500. What is the annual interest rate?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARG fCLEARG
g gÂ
25gA 25gA
612.77ÞP 612.77ÞP
75500$¼ 75500$¼ 0.72 Canadian mortgage factor.
6n0P 0P
200Þ$ 12nM
M:$+ 2n¼§2³ 8.75 Annual interest rate.
Balance Remaining at End of Specified
Period
Example 4: A Canadian mortgage has monthly payments of $612.77 at 8.75% interest.
The principal amount is $75,500. What will be the outstanding balance remaining at the
end of 10 years?
Canadian Mortgages 133
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARG fCLEARG
g gÂ
6n200\$ 2n8.75z2¼
8.75+ÞM¼ 1$M12n¼ 0.72 Canadian mortgage factor.
612.77ÞP 612.77ÞP
10gA 10gA
75500$M 75500$M -61,877.18 Outstanding balance remaining
at the end of 10 years.
134
Miscellaneous
Learning Curve for Manufacturing Costs
Many production process costs vary with output according to the "learning curve"
equation. The production team becomes more proficient in manufacturing a given item as
more and more of them are fabricated and costs may be expected to decrease by a
predictable amount. The learning factor, r, characterizes the learning curve. For instance,
if r =.80 the curve is called an 80% learning curve.
It is readily apparent that the learning, or experience curve, has many uses in setting
production standards, forecasting costs, setting prices, etc. Note, however, that the
learning factor may change, especially after large numbers have been produced.
It the cost of the first unit of a run, C1, and the learning curve factor, r, are known, the
following procedure can be used to calculate the cost of the nth item:
1. Key in the cost of the first item, C1 and press \(³).
2. Key in the number of units produced, n, and press \(³).
RPN Mode:
3. Key in the learning factor, r, and press g°2g°z.
4. Then press q§ to calculate the cost of the nth unit, Cn.
ALG Mode:
3. Key in the learning factor, r, and press g°z2g°q.
4. Then press ~~§~³to calculate the cost of the nth unit, Cn.
Example 1: An electronic manufacturer begins a pilot run on a new instrument. From
past experience he expects the process to have a learning factor, r, or 0.90. If the first unit
costs $875 to produce, what is the expected cost of the 100th unit?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
875\ 875³ 875.00
100\ 100³ 100.00
.9g°2g°z .9g°z2g°q -0.15
q§ ~~§~³ 434.51 Cost of the 100th unit.
If the cost of the first unit, C1, and the nth unit, Cn, are known the learning factor may be
calculated. In addition, it is possible to calculate Cij, the average cost of the ith thru jth
Miscellaneous 135
unit. These calculations may be rapidly done with the following HP 12C Platinum
program:
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
g° 001, 43 23 g° 001, 43 23
2 002, 2 z 002, 10
g° 003, 43 23 2 003, 2
z 004, 10 g° 004, 43 23
?2 005, 44 2 ³ 005, 36
d 006, 33 ?2 006, 44 2
~ 007, 34 d 007, 33
?1 008, 44 1 z 008, 10
z 009, 10 ~ 009, 34
g° 010, 43 23 ?1 010, 44 1
:2 011, 45 2 ³ 011, 36
z 012, 10 g° 012, 43 23
g> 013, 43 22 z 013, 10
?2 014, 44 2 :2 014, 45 2
g(000 015,43,33,000 ³ 015, 36
:2 016, 45 2 g> 016, 43 22
g° 017, 43 23 ?2 017, 44 2
2 018, 2 g(000 018,43,33,000
g° 019, 43 23 :2 019, 45 2
z 020, 10 g° 020, 43 23
q 021, 21 z 021, 10
:1 022, 45 1 2 022, 2
§ 023, 20 g° 023, 43 23
g(000 024,43,33,000 ³ 024, 36
?3 025, 44 3 ~ 025, 34
~ 026, 34 q 026, 21
?4 027, 44 4 ~ 027, 34
:2 028, 45 2 § 028, 20
g° 029, 43 23 :1 029, 45 1
2 030, 2 ³ 030, 36
g° 031, 43 23 g(000 031,43,33,000
z 032, 10 ?3 032, 44 3
1 033, 1 ~ 033, 34
+ 034, 40 ?4 034, 44 4
?0 035, 44 0 :2 035, 45 2
q 036, 21 g° 036, 43 23
:3 037, 45 3 z 037, 10
:0 038, 45 0 2 038, 2
136 Miscellaneous
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
q 039, 21 g° 039, 43 23
- 040, 30 + 040, 40
:0 041, 45 0 1 041, 1
z 042, 10 ³ 042, 36
:4 043, 45 4 ?0 043, 44 0
:3 044, 45 3 ~ 044, 34
- 045, 30 q 045, 21
z 046, 10 ~ 046, 34
:1 047, 45 1 ³ 047, 36
§ 048, 20 :3 048, 45 3
g(000 049,43,33,000 q 049, 21
fs :0 050, 45 0
³ 051, 36
~ 052, 34
- 053, 30
~ 054, 34
z 055, 10
:0 056, 45 0
³ 057, 36
:4 058, 45 4
- 059, 30
:3 060, 45 3
³ 061, 36
~ 062, 34
z 063, 10
~ 064, 34
§ 065, 20
:1 066, 45 1
³ 067, 36
fs
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: K+1 R1: C1 R
2: r
R3: i R
4: j R
5-R.3: Unused
Miscellaneous 137
Program Instructions:
1. Key in the program.
Note: If the average costs are not going to be calculated:
RPN: lines 25 through 48 need not be keyed in
ALG: lines 32 through 67 need not be keyed in
2. To calculate r, the learning factor, if C1 and Cn are known:
a.
Key in C1, the cost of the first unit and press \(³).
b.
Key in Cn, the cost of the nth unit and press \(³).
c.
Key in n, the number of units and press t to calculate r, the learning factor.
3. To calculate the cost of the nth unit when C1 and r are known:
a.
Key in C1 and press ?1. Key in r and press ?2. (Note: This step may be
skipped if step 2 has just been done).
b. Key in the number of units, n and calculate Cn, the cost of the nth unit by pressing
RPN: g(016t.
ALG: g(019t.
4. To calculate the average cost per unit of the ith through jth unit, Cij, if C1 and r are
known.
a.
Key in C1 and press ?1. Key in r and press ?2. (Note: This step may be
skipped if step 2 has just been done).
b.
Key in the number of the last unit of the batch, j and press \(³).
c. Key in the number of the first unit of the batch, i, and calculate the average cost per
unit by pressing
RPN: g(025t.
ALG: g(032t.
Example 2: The electronic manufacturer cited in example 1 found that the 100th
instrument actually cost $395 to manufacture. Find the actual learning factor, r, the cost of
the 500th unit and the average cost of units 500 thru 1000. (Recall that C1 was $875).
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
875\ 875³ 875.00
395\ 395³ 395.00
100t 100t 0.89 Actual r.
500g(016t 500g(019t 299.14 Cost of the 500th unit.
1000\ 1000³ 1000.00
500g(025t 500g(032t 280.00 Average cost of the 500th thru
1000th unit.
138 Miscellaneous
Queuing and Waiting Theory
Waiting lines, or queues, cause problems in many marketing situations. Customer
goodwill, business efficiency, labor and space considerations are only some of the
problems which may be minimized by proper application of queuing theory.
Although queuing theory can be complex and complicated subject, handheld calculators
can be used to arrive at helpful decisions.
One common situation that we can analyze involves the case of several identical stations
serving customers, where the customers arrive randomly in unlimited numbers. Suppose
there are n (1 or more) identical stations serving the customers. λ
is the arrival rate
(Poisson input) and µ is the service rate (exponential service). We will assume that all
customers are served on a first-come, first-served basis and wait in a single line (queue)
then are directed to whichever station is available. We also will assume that no customers
are lost from the queue. This situation, for instance, would be closely approximated by
customers at some banking operations.
The formulas for calculating some of the necessary probabilities are too complex for
simple keystroke solution. However, tables listing these probabilities are available and
can be used to aid in quick solutions. Using the assumptions outlined above and a suitable
table giving mean waiting time as a multiple of mean service (see page 512 of the
Reference) the following keystroke solutions may be obtained:
RPN Mode:
1. Key in the arrival rate of customers, λ, and press \.
2. Key in the service rate, µ, and press z to calculate ρ, the intensity factor. (Note ρ
must be less than n for valid results, otherwise the queue will lengthen without limit).
3. Key in n, the number of servers and press z to calculate ρ/n.
4. For a given n and ρ/n find the mean waiting time as a multiple of mean service time
from the table. Key it in and press \.
5. Calculate the average waiting time in the queue by keying in the service rate, µ, and
pressing ?1z?2.
6. Calculate the average waiting time in the system by pressing :1y+.
7. Key in λ and press :2§ to calculate the average queue length.
8. Key in ρ, the intensity factor (from step 2 above) and press + to calculate the
average number of customers in the system.
Miscellaneous 139
ALG Mode:
1. Key in the arrival rate of customers, λ, and press z.
2. Key in the service rate, µ, and press z to calculate ρ, the intensity factor. (Note ρ
must be less than n for valid results, otherwise the queue will lengthen without limit).
3. Key in n, the number of servers and press ³ to calculate ρ/n.
4. For a given n and ρ/n find the mean waiting time as a multiple of mean service time
from the table. Key it in and press z.
5. Calculate the average waiting time in the queue by keying in the service rate, µ, and
pressing ?1+?2.
6. Calculate the average waiting time in the system by pressing :1y³.
7. Key in λ and press §:2+ to calculate the average queue length.
8. Key in ρ, the intensity factor (from step 2 above) and press ³ to calculate the
average number of customers in the system.
Reference:
Richard E Trueman, "An Introduction to Quantitative Methods for Decision Making,"
Holt, Rinehart and Winston, New York, 1977
Example 1: Bank customers arrive at a bank on an average of 1.2 customers per minute.
They join a common queue for three tellers. Each teller completes a transaction at the rate
of one customer every 2 minutes (0.5 customers per minute). What is the average waiting
time in the queue? In the system? What is the average number of customers in the queue?
In the system?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
1.2\ 1.2z 1.20
.5z .5z 2.40
ρ
, intensity factor.
3z 3³ 0.80
ρ
/ n
From Table 12.2, page 512 of the reference, the mean waiting time as a multiple of mean
service time for n = 3, ρ/n = 0.8 is 1.079. (Note S is used instead of n in the reference's
notation).
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
1.079\ 1.079z 1.08
.5?1z?2 .5?1+?2 2.16 Average wait in queue (min).
:1y+ :1y³ 4.16 Average wait in system (min).
1.2:2§ 1.2§:2+ 2.59 Average queue length.
2.4+ 2.4³ 4.99 Average # of customers in
system.
140 Miscellaneous
If the number of servers is limited to one, with other conditions remaining the same
(unlimited queue, Poisson arrival, exponential service), the average queue length can be
readily calculated without reference to tables:
RPN Mode:
1. Key in the arrival rate, λ and press ?1.
2. Key in the service rate, µ and press ?2
z\\2q~ 1~-z to calculate the average number of customers
waiting in queue at any one time.
3. Press :1z to calculate the average waiting time.
4. Press :2y+ to calculate the average total time the customer spends in the
system.
5. Press :1§ to calculate the average number of customers in the system.
ALG Mode:
1. Key in the arrival rate, λ and press ?1z.
2. Key in the service rate, µ and press ?2³y-g’~³y to calculate
the average number of customers waiting in queue at any one time.
3. Press z:1+ to calculate the average waiting time.
4. Press :2y§ to calculate the average total time the customer spends in the
system.
5. Press :1³ to calculate the average number of customers in the system.
Example 2: A small grocery store has but a single check-out counter. Customers arrive at
a rate of 1 every 2 minutes (λ
= .5) and, on the average, customers can be checked out at a
rate of .9 per minute (µ). What is the average number of customers in the waiting line at
any time? The average waiting time? What is the average total time for a customer to wait
and be checked out? The average number of customers in the system?
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
.5?1 .5?1z 0.50
.9?2z\ .9?2
\2q~ ³ 0.56 (intensity factor, ρ)
1~ y-g’
-z ~³y
0.69 Average # customers waiting in
queue.
:1z z:1+ 1.39 Average waiting time.
:2y+ :2y§ 2.50 Average total time in the
system.
:1§ :1³ 1.25 Average # customers in system.
Miscellaneous 141
With an HP 12C Platinum program one can readily calculate the necessary probabilities
for this type of problem (dispensing with the use of tables) and perform additional
calculations as well.
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
fs fs
fCLEARÎ 000, fCLEARÎ 000,
1 001, 1 1 001, 1
?-0 002,44 33 0 ?-0 002,44 30 0
:.0 003,45 48 0 :0 003, 45 0
:0 004, 45 0 0 004, 0
0 005, 0 go 005, 43 34
go 006, 43 34 g(008 006,43,33,008
g(009 007,43,33,009 g(017 007,43,33,017
g(016 008,43,33,016 :.0 008,45 48 0
+ 009, 40 q 009, 21
q 010, 21 :0 010, 45 0
gF 011, 43 40 z 011, 10
ge 012, 43 3 :0 012, 45 0
z 013, 10 ge 013, 43 3
_ 014, 49 ³ 014, 36
g(001 015,43,33,001 _ 015, 49
:.0 016,45 48 0 g(001 016,43,33,001
:7 017, 45 7 :.0 017,45 48 0
q 018, 21 z 018, 10
1 019, 1 :7 019, 45 7
:.0 020,45 48 0 - 020, 30
:7 021, 45 7 1 021, 1
z 022, 10 ³ 022, 36
- 023, 30 Þ 023, 16
z 024, 10 :.0 024,45 48 0
:7 025, 45 7 q 025, 21
ge 026, 43 3 :7 026, 45 7
z 027, 10 z 027, 10
?6 028, 44 6 ~ 028, 34
:2 029, 45 2 z 029, 10
+ 030, 40 :7 030, 45 7
y 031, 22 ge 031, 43 3
?1 032, 44 1 ³ 032, 36
:6 033, 45 6 ?6 033, 44 6
§ 034, 20 + 034, 40
?2 035, 44 2 :2 035, 45 2
:.0 036,45 48 0 ³ 036, 36
142 Miscellaneous
12c platinum / 12C
RPN KEYSTROKES DISPLAY 12c platinum
ALG KEYSTROKES DISPLAY
§ 037, 20 y 037, 22
:7 038, 45 7 ?1 038, 44 1
:.0 039,45 48 0 ?2 039, 44 2
- 040, 30 :6 040, 45 6
z 041, 10 ?§2 041,44 20 2
?3 042, 44 3 :7 042, 45 7
:.0 043,45 48 0 - 043, 30
+ 044, 40 :.0 044,45 48 0
?4 045, 44 4 ³ 045, 36
:8 046, 45 8 :.0 046,45 48 0
z 047, 10 z 047, 10
?5 048, 44 5 ~ 048, 34
:3 049, 45 3 § 049, 20
:8 050, 45 8 :2 050, 45 2
z 051, 10 + 051, 40
?6 052, 44 6 ?3 052, 44 3
t 053, 31 :.0 053,45 48 0
:8 054, 45 8 z 054, 10
:7 055, 45 7 ?4 055, 44 4
:9 056, 45 9 :8 056, 45 8
§ 057, 20 ³ 057, 36
- 058, 30 ?5 058, 44 5
§ 059, 20 :3 059, 45 3
g> 060, 43 22 z 060, 10
:2 061, 45 2 :8 061, 45 8
§ 062, 20 ³ 062, 36
g(053 063,43,33,053 ?6 063, 44 6
fs t 064, 31
:7 065, 45 7
§ 066, 20
:9 067, 45 9
- 068, 30
:8 069, 45 8
§ 070, 20
~ 071, 34
³ 072, 36
Þ 073, 16
g> 074, 43 22
§ 075, 20
:2 076, 45 2
³ 077, 36
g(064 078,43,33,064
fs
Miscellaneous 143
REGISTERS
n: Unused i: Unused PV: Unused PMT: Unused
FV: Unused R0: K R1: P0 R
2: Pb
R3: Lq R
4: L R5: T R6: Used, Tq
R7: n R
8: λ R
9: µ R
.0: ρ
R.1: Unused
Program Instructions:
1. Key in the program and press fCLEARH.
2. Key in the number of servers, n and press ?0?7.
RPN Mode:
3. Key in the arrival rate of customers, λ and press ?8.
4. Key in the service rate of each server, µ and press ?9.
5. Press z?.0 to calculate and store ρ the intensity factor.
ALG Mode:
3. Key in the arrival rate of customers, λ and press ?8z.
4. Key in the service rate of each server, µ and press ?9.
5. Press ³?.0 to calculate and store ρ the intensity factor.
6. Press t to see Tq, the average waiting time in the queue. Display P0, probability
that all servers are idle, by pressing :1. Display Pb, probability that all servers are
busy by pressing :2. Display Lq, average number waiting in the queue by pressing
:3. Display L, the average number in the system (waiting and being served), by
pressing :4.
Display T, average total time through the system, by pressing :5. Tq, the average
waiting time in the queue, may again be displayed by pressing :6.
7. If desired, calculate P(t), the probability of waiting longer than a given time, by keying
in the time and pressing t.
8. Repeat step 7 for other times of interest.
Example 3: Using the data from example 1 of the keystroke solutions verify the data
obtained. In addition, obtain P0, the probability that none of the tellers are busy, and Pb
the probability that all the tellers are busy. What is the probability that a customer will
have to wait 2 minutes or more?
144 Miscellaneous
12c platinum / 12C
RPN Keystrokes 12c platinum
ALG Keystrokes Display Comments
fCLEARH fCLEARH 0.00
3?0?7 3?0?7 3.00 n
1.2?8 1.2?8z 1.20 λ
.5?9 .5?9 0.50
µ
z?.0 ³?.0 2.40
ρ
t t 2.16 Tq average waiting time in queue.
:1 :1 0.06 P0 probability all servers are idle.
:2 :2 0.65 Pb probability all servers are
busy.
:3 :3 2.59 Lq average # waiting in queue.
:4 :4 4.99 L, average # waiting in system.
:5 :5 4.16 T, average total time in system.
2t 2t 0.36 Probability of having to wait 2
minutes or more.
145
Appendix A
Algebraic Versions of Programs from
Part III of the Owner's Handbook
About this Appendix
This appendix contains algebraic versions of the eleven programs found in Part III of the
HP12C Platinum Owner's Handbook and Problem-Solving Guide. It does not cover the
step-by-step examples given in Part III.
These programs are solely for the HP 12C Platinum, and work properly only when the
calculator is set to ALG mode.
They should be tested by running the corresponding program examples given in the
HP12C Platinum Owner's Handbook and Problem-Solving Guide. They work exactly the
same as the RPN versions. The instructions for running these programs are not included
here. They are simply listed with reference to the relevant section in the HP12C Platinum
Owner's Handbook and Problem-Solving Guide. The register usage is the same as in the
RPN versions.
In order to execute miscellaneous side calculations which are done during the program
examples, these additional steps are required in algebraic mode:
1. The first three depreciation programs specify a side calculation to calculate the total
depreciation through the current year - the algebraic version of this is:
:$+:3-~-:M³.
2. Section 14 - the Advance Payments with Residual-Solving for Payment program
Example 1 stores 15/12 in R1 and Example 2 stores 18/12 in R1. The algebraic
keystrokes are: 15z12³?1 and 18z12³?1.
3. At the end of the bond programs the total price is obtained by pressing: +~³.
4. Section 16 - the 30/360 Day Basis Bonds program Example 2 stores 93 ⅜ in R1. The
algebraic keystrokes are: 3z8+93³?1.
The program listings have been formatted in double columns and apart from one instance
the listings do not span pages, thus making key entry convenient.
146 Appendix A
Algebraic Mode Programs
Section 12: The Rent or Buy Decision
ALG KEYSTROKES DISPLAY ALG KEYSTROKES DISPLAY
fs - 032, 30
fCLEARÎ 000, :4 033, 45 4
M 001, 15 - 034, 30
M 002, 15 :5 035, 45 5
:n 003, 45 11 + 036, 40
?0 004, 44 0 :8 037, 45 8
:2 005, 45 2 - 038, 30
gA 006, 43 11 ~ 039, 34
:3 007, 45 3 P 040, 14
gC 008, 43 12 d 041, 33
:$ 009, 45 13 Þ 042, 16
- 010, 30 - 043, 30
:1 011, 45 1 :7 044, 45 7
$ 012, 13 b 045, 25
:M 013, 45 15 - 046, 30
0 014, 0 :$ 047, 45 13
M 015, 15 M 048, 15
P 016, 14 t 049, 31
d 017, 33 :0 050, 45 0
:0 018, 45 0 gA 051, 43 11
gA 019, 43 11 :1 052, 45 1
f! 020, 42 11 Þ 053, 16
~ 021, 34 - 054, 30
d 022, 33 :6 055, 45 6
z 023, 10 $ 056, 13
~ 024, 34 ¼ 057, 12
- 025, 30 :gC 058,45,43 12
:4 026, 45 4 t 059, 31
§ 027, 20 :9 060, 45 9
:.0 028,45 48 0 gC 061, 43 12
b 029, 25 M 062, 15
³ 030, 36 M 063, 15
:P 031, 45 14 fs
Appendix A 147
Section 13: Straight-Line Depreciation
ALG KEYSTROKES DISPLAY ALG KEYSTROKES DISPLAY
fs - 023, 30
fCLEARÎ 000, :1 024, 45 1
z 001, 10 n 025, 11
1 002, 1 :0 026, 45 0
2 003, 2 gm 027, 43 35
³ 004, 36 g(038 028,43,33,038
?1 005, 44 1 :2 029, 45 2
~ 006, 34 gu 030, 43 31
?2 007, 44 2 :0 031, 45 0
- 008, 30 fV 032, 42 23
1 009, 1 t 033, 31
³ 010, 36 1 034, 1
?0 011, 44 0 ?+0 035,44 40 0
1 012, 1 ?+2 036,44 40 2
fV 013, 42 23 g(029 037,43,33,029
§ 014, 20 :2 038, 45 2
:1 015, 45 1 gu 039, 43 31
³ 016, 36 :$ 040, 45 13
?3 017, 44 3 - 041, 30
:$ 018, 45 13 :M 042, 45 15
- 019, 30 ³ 043, 36
~ 020, 34 :3 044, 45 3
$ 021, 13 g(033 045,43,33,033
:n 022, 45 11 fs
148 Appendix A
Section 13: Declining-Balance Depreciation
ALG KEYSTROKES DISPLAY ALG KEYSTROKES DISPLAY
fs $ 021, 13
fCLEARÎ 000, :0 022, 45 0
z 001, 10 gm 023, 43 35
1 002, 1 g(034 024,43,33,034
2 003, 2 :2 025, 45 2
³ 004, 36 gu 026, 43 31
?1 005, 44 1 :0 027, 45 0
~ 006, 34 f# 028, 42 25
?2 007, 44 2 t 029, 31
- 008, 30 1 030, 1
1 009, 1 ?+0 031,44 40 0
³ 010, 36 ?+2 032,44 40 2
?0 011, 44 0 g(025 033,43,33,025
1 012, 1 :2 034, 45 2
f# 013, 42 25 gu 035, 43 31
§ 014, 20 :$ 036, 45 13
:1 015, 45 1 - 037, 30
³ 016, 36 :M 038, 45 15
?3 017, 44 3 ³ 039, 36
:$ 018, 45 13 :3 040, 45 3
- 019, 30 g(029 041,43,33,029
~ 020, 34 fs
Appendix A 149
Section 13: Sum-of-the-Years-Digits Depreciation
ALG KEYSTROKES DISPLAY ALG KEYSTROKES DISPLAY
fs - 023, 30
fCLEARÎ 000, :1 024, 45 1
z 001, 10 n 025, 11
1 002, 1 :0 026, 45 0
2 003, 2 gm 027, 43 35
³ 004, 36 g(038 028,43,33,038
?1 005, 44 1 :2 029, 45 2
~ 006, 34 gu 030, 43 31
?2 007, 44 2 :0 031, 45 0
- 008, 30 fÝ 032, 42 24
1 009, 1 t 033, 31
³ 010, 36 1 034, 1
?0 011, 44 0 ?+0 035,44 40 0
1 012, 1 ?+2 036,44 40 2
fÝ 013, 42 24 g(029 037,43,33,029
§ 014, 20 :2 038, 45 2
:1 015, 45 1 gu 039, 43 31
³ 016, 36 :$ 040, 45 13
?3 017, 44 3 - 041, 30
:$ 018, 45 13 :M 042, 45 15
- 019, 30 ³ 043, 36
~ 020, 34 :3 044, 45 3
$ 021, 13 g(033 045,43,33,033
:n 022, 45 11 fs
150 Appendix A
Section 13: Full- and Partial- Year Depreciation with Crossover
ALG KEYSTROKES DISPLAY ALG KEYSTROKES DISPLAY
fs d 040, 33
fCLEARÎ 000, t 041, 31
z 001, 10 1 042, 1
1 002, 1 ?+2 043,44 40 2
2 003, 2 ?-0 044,44 30 0
³ 004, 36 f# 045, 42 25
?6 005, 44 6 ?+1 046,44 40 1
:n 006, 45 11 ?5 047, 44 5
- 007, 30 :$ 048, 45 13
~ 008, 34 - 049, 30
³ 009, 36 :M 050, 45 15
?4 010, 44 4 z 051, 10
d 011, 33 :4 052, 45 4
?0 012, 44 0 ³ 053, 36
1 013, 1 go 054, 43 34
?-0 014,44 30 0 g(057 055,43,33,057
?2 015, 44 2 g(069 056,43,33,069
?3 016, 44 3 d 057, 33
f# 017, 42 25 0 058, 0
§ 018, 20 :0 059, 45 0
:6 019, 45 6 go 060, 43 34
³ 020, 36 g(090 061,43,33,090
?1 021, 44 1 :$ 062, 45 13
:$ 022, 45 13 - 063, 30
- 023, 30 :5 064, 45 5
~ 024, 34 $ 065, 13
$ 025, 13 1 066, 1
:1 026, 45 1 ?-4 067,44 30 4
:$ 027, 45 13 g(043 068,43,33,043
- 028, 30 :4 069, 45 4
:M 029, 45 15 n 070, 11
³ 030, 36 0 071, 0
~ 031, 34 ?6 072, 44 6
:0 032, 45 0 1 073, 1
1 033, 1 ?-2 074,44 30 2
go 034, 43 34 ?+0 075,44 40 0
g(042 035,43,33,042 :5 076, 45 5
d 036, 33 ?-1 077,44 30 1
d 037, 33 :3 078, 45 3
1 038, 1 fV 079, 42 23
gu 039, 43 31 ?+1 080,44 40 1
Appendix A 151
Full- and partial-Year Depreciation with Crossover (continued)
ALG KEYSTROKES DISPLAY ALG KEYSTROKES DISPLAY
1 081, 1 d 091, 33
?-0 082,44 30 0 :2 092, 45 2
?+2 083,44 40 2 gu 093, 43 31
?+3 084,44 40 3 d 094, 33
d 085, 33 t 095, 31
:0 086, 45 0 :6 096, 45 6
1 087, 1 gm 097, 43 35
go 088, 43 34 g(078 098,43,33,078
g(078 089,43,33,078 g(062 099,43,33,062
d 090, 33 fs
Section 14: Lease with Advance Payments - Solving For Payment
ALG KEYSTROKES DISPLAY ALG KEYSTROKES DISPLAY
fs Þ 010, 16
fCLEARÎ 000, P 011, 14
g 001, 43 8 $ 012, 13
fCLEARG 002, 42 34 + 013, 40
:0 003, 45 0 :1 014, 45 1
- 004, 30 z 015, 10
:1 005, 45 1 :3 016, 45 3
n 006, 11 ~ 017, 34
:2 007, 45 2 ³ 018, 36
¼ 008, 12 fs
1 009, 1
Section 14: Lease with Advance Payments - Solving For Yield
ALG KEYSTROKES DISPLAY ALG KEYSTROKES DISPLAY
fs P 008, 14
fCLEARÎ 000, § 009, 20
g 001, 43 8 :1 010, 45 1
fCLEARG 002, 42 34 - 011, 30
:0 003, 45 0 :3 012, 45 3
- 004, 30 $ 013, 13
:1 005, 45 1 ¼ 014, 12
n 006, 11 :gC 015,45,43 12
:2 007, 45 2 fs
152 Appendix A
Section 14: Advance Payments With Residual - Solving for Payment
ALG KEYSTROKES DISPLAY ALG KEYSTROKES DISPLAY
fs M 015, 15
fCLEARÎ 000, :n 016, 45 11
g 001, 43 8 - 017, 30
fCLEARG 002, 42 34 :4 018, 45 4
:0 003, 45 0 n 019, 11
n 004, 11 1 020, 1
:1 005, 45 1 Þ 021, 16
¼ 006, 12 P 022, 14
:3 007, 45 3 $ 023, 13
M 008, 15 + 024, 40
$ 009, 13 :4 025, 45 4
+ 010, 40 z 026, 10
:2 011, 45 2 :5 027, 45 5
³ 012, 36 ~ 028, 34
?5 013, 44 5 ³ 029, 36
0 014, 0 fs
Section 15: Nominal Rate Converted to Effective Rate
ALG KEYSTROKES DISPLAY ALG KEYSTROKES DISPLAY
fs 1 007, 1
fCLEARÎ 000, $ 008, 13
fCLEARG 001, 42 34 M 009, 15
n 002, 11 1 010, 1
~ 003, 34 n 011, 11
z 004, 10 ¼ 012, 12
~ 005, 34 fs
¼ 006, 12
Appendix A 153
Section 16: 30/360 Day Basis Bonds
ALG KEYSTROKES DISPLAY ALG KEYSTROKES DISPLAY
fs ³ 026, 36
fCLEARÎ 000, ?6 027, 44 6
fCLEARG 001, 42 34 :6 028, 45 6
g× 002, 43 7 :0 029, 45 0
:2 003, 45 2 gm 030, 43 35
z 004, 10 g(041 031,43,33,041
2 005, 2 z 032, 10
P 006, 14 2 033, 2
?6 007, 44 6 ¼ 034, 12
+ 008, 40 $ 035, 13
:5 009, 45 5 Þ 036, 16
M 010, 15 - 037, 30
:3 011, 45 3 ~ 038, 34
:4 012, 45 4 ³ 039, 36
gÒ 013, 43 26 g(000 040,43,33,000
d 014, 33 d 041, 33
z 015, 10 + 042, 40
1 016, 1 :1 043, 45 1
8 017, 8 ³ 044, 36
0 018, 0 Þ 045, 16
n 019, 11 $ 046, 13
gT 020, 43 24 ¼ 047, 12
1 021, 1 § 048, 20
- 022, 30 2 049, 2
~ 023, 34 ³ 050, 36
§ 024, 20 fs
:6 025, 45 6
154 Appendix A
Section 16: Annual Coupon Bonds
ALG KEYSTROKES DISPLAY ALG KEYSTROKES DISPLAY
fs gÒ 020, 43 26
fCLEARÎ 000, ?7 021, 44 7
fCLEARG 001, 42 34 :6 022, 45 6
g 002, 43 8 :4 023, 45 4
:0 003, 45 0 gÒ 024, 43 26
n 004, 11 z 025, 10
:2 005, 45 2 :7 026, 45 7
P 006, 14 n 027, 11
:1 007, 45 1 0 028, 0
¼ 008, 12 P 029, 14
:3 009, 45 3 M 030, 15
M 010, 15 :n 031, 45 11
$ 011, 13 § 032, 20
:5 012, 45 5 :2 033, 45 2
- 013, 30 Þ 034, 16
Æ 014, 26 + 035, 40
6 015, 6 t 036, 31
Þ 016, 16 ~ 037, 34
³ 017, 36 ³ 038, 36
?6 018, 44 6 Þ 039, 16
:5 019, 45 5 fs
155
Appendix B
Formulas Used
Real Estate
Wrap-Around Mortgage
n1 = number of years remaining in original mortgage.
PMT1 = yearly payment of original mortgage.
PV1 = remaining balance of original mortgage.
n2 = number of years in wrap-around mortgage.
PMT2 = yearly payment of wrap-around mortgage.
PV2 = total amount of wrap-around mortgage.
r = interest rate of wrap-around mortgage as a decimal.
FV = balloon payment.
() () ()
2
1
1
2
2
12 n
r1FV
r
n
r11PMT
r
n
r11PMT
PVPV −
++
−
+−
−
−
+−
=−
After-Tax Cash Flows
ATCFk = After-Tax Cash Flow for kth year.
Intk = interest for kth year.
Depk = depreciation for kth year.
r = appropriate tax rate.
NOI = Net Operating Income.
ATCFk = NOI (1 − r) − 12 x PMT + r x (Intk + Depk).
After-Tax Net Cash Proceeds of Resale
CO = capital purchase.
CPR = sales price − closing costs.
r = marginal tax rate.
c= capital gains tax rate.
NCPR = CPR − remaining balance of mortgage.
ATNCPR = NCPR − r x (Total Dep. − SL Dep.) − c x (CPR − CO + SL Dep.)
= NCPR − [c x (CPR − CO) + r x (Total Dep.) +(c − r) x (SL Dep.) ]
156 Appendix B
Lending
Loans With a Constant Amount Paid Towards Principal
BALk = remaining balance after time period k.
CPMT = Constant payment to principal.
BALk = PV − (k x CPMT)
kth payment to interest = i (BALk) = (PMTi)k
kth total payment = CPMT + (PMTi)k
Add-On Interest Rate to APR
r = add-on rate as a decimal.
n = number of monthly payments.
APR = 1200i, where i is the solution in the following equation:
(
)
i
i
r
n
nn−
+−
=
+
11
12
1
Add-On to APR with Credit Life
CL = credit life as decimal.
AMT = loan amount.
FC = finance charge.
GAMT
rCL
n
CL
n
r
n
=×
××
−×
−
+
2
1212
1
12
1
PMT
n
G=
lifecredit ofamount
12 =
×× nCLG
FC = (G − AMT − CL)
Rule of 78's Rebate
PV = finance charge.
Ik = interest charged at month k.
n = number of months in loan.
()
()
PV
nn
kn
Ik1
12
+
+−
=
Appendix B 157
(
)
2
k
Ikn
Rebate −
=
BALk = (n − k) × PMT − Rebatek
Graduated Payment Mortgage
n = total number of payments in the loan
I = interest rate per payment period, as a decimal
A = number of payments per year
B = number of years that payments increase
C = percentage increase in periodic payments (as a decimal)
PMT1 = amount of the first payment
PV = amount of the loan.
() () () ()
()
+
+−
+
+
−+
+−
=
−−
−
AB
ABn
B
BA
I
I
I
C
Q
Q
I
I
PMTPV
1
11
1
11
11
)(
1
where:
()
1
1
1−
+
+
=A
I
C
Q
Skipped Payments
A = number of payments per year.
B = number of years.
C = annual percentage rate as decimal.
D = periodic payment amount.
E = loan amount.
K = number of last payment before payments close the first time.
L = number of skipped payment.
+−
=−AB
A
C
E
D
11
END
−
++
+−
+
−
+
×−−−
1111
11
KLAKAA
A
A
C
A
C
A
C
A
C
A
C
A
C
D
D
+
=
1
END
BEGIN
158 Appendix B
Savings
Compounding Periods Different From Payment Periods
C = number of compounding periods per year.
P = number of payment periods per year.
i = periodic interest rate, expressed as a percentage.
r = i / 100, periodic interest rate expressed as a decimal.
iPMT = ((1 + r / C)C/P − 1)100
Investment Analysis
Lease vs. Purchase
PMTp = loan payment for purchase.
PMTL = lease payment.
In = interest portion of PMTp for period n.
Dn = depreciation for period n.
Mn = maintenance for period n.
T = marginal tax rate.
Net purchase advantage =
()
∑
=+
−
k
nn
i
nn
11
)(owning ofcost )(leasing ofcost
Cost of leasing(n) = (1 − T) PMTL
Cost of owning(n) = PMTp − T(In + Dn) + (1 − T)Mn
Break-Even Analysis and Operating Leverage
GP = Gross Profit.
P = Price per unit.
V = Variable costs per unit.
F = Fixed costs.
U = number of Units.
OL = Operating Leverage.
GP = U(P − V) − F
()
()
FVPU
VPU
OL −−
−
=
Profit and Loss Analysis
Net income = (1 − tax) (net sales price − manufacturing expense − operating expense)
Net sales price = list price(1 − discount rate)
where operating expense represents a percentage of net sales price.
Appendix B 159
Securities and Options
Discounted Notes
Price (given discount rate)
B = number of days in year (annual basis).
DR = discount rate (as a decimal).
DSM = number of days from settlement date to maturity date.
P = dollar price per $100 per value.
RV = redemption value per $100 par value.
[]
××−= B
DSM
RVDRRVP
Yield (given price)
B = number of days in year (annual basis).
DSM = number of days from settlement date to maturity date.
P = dollar price per $100 par value.
RV = redemption value per $100 par value.
Y = annual yield of investment with security held to maturity (as a decimal).
×
−
=DSM
B
P
PRV
Y
Black-Scholes Formula for Valuing European Options
P = current asset price.
r%= risk-free rate (continuous, per time unit).
s% = volatility (continuous, per time unit).
T = term of option (same time unit as r% and s%).
X = exercise price of option.
N(z)= probability that a unit normal random variable is less than z.
Call Value =
(
)
(
)
21 dNQdNP
×
−
×
Put Value = Call Value PQ
−
+
where:
()
2///
1vvQPLNd
+
=, vdd
−
=
12
()
100/%rT
XeQ ×−
=, Tsv ×= 100/%
160 Appendix B
Forecasting
Simple Moving Average
average. moving x =
average. movingin elements ofnumber
=m
m
xxxx
xm
++++
=...
321
1
m
xxxx
xm1432
2
... −
++++
=
etc.
Seasonal Variation Factors Based on a Centered Moving Average
average moving centered
c=x
m = number of elements in the centered moving average.
()
m
x
xxx
x
x
m
m
c2
...
2
1
32
1+
+++++
=
SV = Seasonal variation factor.
xi = value of the ith data point.
point. datath theof average moving centered ixi=
i
i
x
x
SV =
Gompertz Curve Trend Analysis
(
)
x
b
cay =
where x, y, a, b, and c are positive.
n
SS
SS
b
/1
12
23
−
−
=
−+
−
=
231
2
231
2
1
exp SSS
SSS
n
c
()( )
()
−
−−
=2
12
1
1
exp
n
bb
SSb
a
where S1, S2, and S3 are:
Appendix B 161
()
1
1
lnlnln
1
1−
−
+== ∑
=b
b
abcnyS
n
n
i
i
()
1
1
lnlnln
2
1
1
2−
−
+== ∑
+=
+
b
b
abcnyS
n
n
ni
n
i
()
1
1
lnlnln
3
12
12
3−
−
+== ∑+=
+
b
b
abcnyS
n
n
ni
n
i
a, b and c are determined by solving the three equations above simultaneously.
Forecasting With Exponential Smoothing
α= smoothing constant (0 < α< 1)
Xt = actual current period usage
1
α1α average, Smoothed −
)
−
(
+
=
ttt SX S
1
Change, t - tt - S S C
=
1
α1α Trend, −
)
−
(
+
=
ttt ΤΧ T
Current period expected usage,
()
ttt TSD α
α1−
+=
Forecast of next period expected usage, ttt TSD
+=
+α
1
ˆ1
Error, ttt XDe −= ˆ
Cumulative error ∑
=
=m
t
t
e
1
2
0 and :conditions Initial 111
=
=
−−− ttt TXS
Pricing Calculations
Markup and Margin Calculations
Ma = margin(%).
Mu = markup(%).
S = selling price.
C = cost.
S
CS
Ma −
=100
C
CS
Mu −
=100
162 Appendix B
100
1Ma
C
S
−
=
+= 100
1Mu
CS
−= 100
1Ma
SC
100
1Mu
S
C
+
=
100
1Mu
Mu
Ma
+
=
100
1Ma
Ma
Mu
−
=
Calculations of List and Net Prices with Discounts
L = List price.
N = Net price.
D = Discount(%).
100
1D
D−=
′
x
DDD
N
L′
××
′
×
′
=...
21
()
′
××
′
×
′
−=
−121 ...
1100
x
xDDDL
N
D
Statistics
Exponential Curve Fit
Bx
Aey =
BxAy += lnln
()( )
()
∑∑
∑∑∑
−
−
=2
21
ln
1
ln
ii
iiii
x
n
x
yx
n
yx
B
Appendix B 163
−= ∑∑
n
x
B
n
y
Aii
ln
exp
Bx
Aey =
ˆ
Logarithmic Curve Fit
(
)
xBAy ln+=
()( )
()
()
∑∑
∑∑∑
−
−
=2
2ln
1
ln
ln
1
ln
ii
iiii
x
n
x
xy
n
xy
B
()
∑∑
−= ii xBy
n
Aln
1
(
)
xBAy ln
ˆ+=
Power Curve Fit
y = AxB (A>0)
(
)
xBAy lnlnln
+
=
()()
()()
()
()
∑∑
∑∑∑
−
−
=2
2ln
1
ln
ln ln
1
ln ln
ii
iiii
x
n
x
yx
n
yx
B
−= ∑∑
n
x
B
n
y
Aii lnln
exp
B
Axy =
ˆ
Standard Error of the Mean
n
S
Sx
x=
n
S
Sy
y=
Mean, Standard Deviation, Standard Error for Grouped Data
mean, ∑
∑
=
i
ii
f
xf
x
standard deviation,
()
1
2
2
−
−
=∑
∑∑
i
iii
xf
xfxf
S
standard error, ∑
=
i
x
xf
S
S
164 Appendix B
Personal Finance
Tax-Free Retirement Account (IRA) or Keogh Plan
n = the number of years to retirement.
i = the compounded annual interest.
PMT = the total annual investment.
FV= future value, after applicable taxes.
r = the assumed tax rate on interest expressed as a decimal.
w = the withdrawal tax rate expressed as a decimal.
For ordinary taxable investment:
() ()
[]
()
[]
{
}
111 11
1−−+−+
−
=n
riri
ri
PMT
FV
For tax-free investment:
(
)()()
[
]
11 1
1−++
−×
=n
ii
i
wPMT
FV
Stock Portfolio Evaluation and Analysis
n = the number of issues held.
Pi = the current market price / share of a stock.
Si = the number of shares of a stock held.
i
β= the beta coefficient of an individual stock.
T = the total present value of a portfolio.
Portfolio beta coefficient:
∑
=
=n
1i
β
βT
SP iii
Canadian Mortgages
r = annual interest rate expressed as a decimal.
monthly factor 1001
2
1
6/1
×
−
+= r
Appendix B 165
Miscellaneous
Learning Curve for Manufacturing Cost
Cn = Cost of the nth unit, C1 = Cost of the first unit.
n = number of units, r = learning factor.
k = ln r / ln 2, k
nnCC 1
=
unit.th th through theofcost average the jiCij =
+
−
−
=++
1
11
1
k
ij
ij
C
C
kk
ij
This formula is only approximate and may give appreciable error at small i.
Queuing and Waiting Theory
n = number of servers.
λ
= arrival rate of customers (Poisson input).
µ
=service rate for each server (exponential service).
ρ
= Intensity factor =
λ
/
µ
(
ρ
< n for valid results).
0
P= Probability that all servers are idle.
b
P= Probability that all servers are busy.
q
L= Average number of customers in queue.
L = Average number of customers in the system (waiting and being served).
q
T= Average waiting time in queue.
T = Average total time through the system.
P(t) = Probability of waiting longer than time t.
1
1
0
0
1 !
−
−
=
−
+= ∑
n
n
k!
P
n
n
k
k
ρ
ρρ
−
=
n
n
P
P
n
b
ρ
ρ
1 !
0
ρ
ρ
−
=n
P
Lb
q
,
ρ
+
=
q
LL ,
λ
/LT
=
,
λ
q
q
L
T=
()
(
)
tn
bePtP
λµ
−−
=
166
Subject Index
Page numbers in bold type indicate primary references: page numbers in regular type
indicate secondary references.
A
About This Handbook 2
Add-On Interest Rate Converted to APR 25, 156
Add-On Rate Loan with Credit Life 27, 156
After-Tax Cash Flows 14, 155
After-Tax Net Cash Proceeds of Resale 19, 155
After-Tax Yield 65
Algebraic Versions of Programs from Part III of the Owner's Handbook 145
APR Converted to Add-On Interest Rate 26
B
Balance Remaining at End of Specified Period 132
Before-Tax Cash Flows 12
Before-Tax Reversions (Resale Proceeds) 13
Black-Scholes Formula for Valuing European Options 69, 159
Bonds: 30/360 Day Basis Bonds 153
Bonds: Annual Coupon Bonds 154
Break-Even Analysis 53, 158
C
Calculations of List and Net prices With Discounts 95, 162
Canadian Mortgages 131, 164
Chi-Square Statistics 109
Combinations 117
Compounding Periods Different From Payment Periods 46, 158
Covariance 114
Curve Fitting 98
D
Depreciation: Declining-Balance Depreciation 148
Depreciation: Full- and Partial- Year Depreciation with Crossover 150
Depreciation: Straight-Line Depreciation 147
Depreciation: Sum-of-the-Years-Digits Depreciation 149
Discounted Notes 67, 159
Subject Index 167
E
Effective Interest Rate (Yield) 132
Exponential Curve Fit 98, 162
F
Forecasting 74, 160
Forecasting with Exponential Smoothing 87, 161
Formulas Used 155
G
Gompertz Curve Trend Analysis 83, 160
Graduated Payment Mortgage 157, 32
H
Homeowners Monthly Payment Estimator 121
I
Income Property Cash Flow Analysis 12
Initial Deposit with Periodic Deposits 40
Interest Rebate - Rule of 78's 30, 156
Introduction 2
Investment Analysis 49, 158
L
Learning Curve for Manufacturing Cost 134, 165
Lease vs. Purchase 49, 158
Leasing: Advance Payments With Residual - Solving for Payment 152
Leasing: Lease with Advance Payments - Solving For Payment 151
Leasing: Lease with Advance Payments - Solving For Yield 151
Lending 24, 156
Loan With a Constant Amount Paid Towards Principal 24, 156
Logarithmic Curve Fit 102, 163
M
Markup and Margin Calculations 92, 161
Mean, Standard Deviation, Standard Error for Grouped Data 106, 163
Miscellaneous 134, 165
N
Normal Distribution 112
Number of Periodic Payments to Fully Amortize a Mortgage 132
Number of Periods to Deplete a Savings Account or to Reach a Specified Balance 41
O
Operating Leverage 59, 158
168 Subject Index
P
Periodic Deposits and Withdrawals 42
Periodic Payment Amount 131
Permutations 116
Personal Finance 121, 164
Portfolio beta coefficient 164
Power Curve Fit 104, 163
Presentation of Algebraic and RPN 2
Pricing Calculations 92, 161
Profit and Loss Analysis 61, 158
Q
Queuing and Waiting Theory 138, 165
R
Random Number Generator 119
Real Estate 7, 155
Real Estate: The Rent or Buy Decision 146
Refinancing 7
Rule of 78's Rebate 156
S
Savings 40, 158
Savings Account Compounded Daily 44, 160
Savings: Nominal Rate Converted to Effective Rate 152
Seasonal Variation Factors Based on a Centered Moving Average 160
Securities and Options 65, 159
Simple Moving Average 74, 160
Skipped Payments 38, 157
Standard Error of the Mean 105, 163
Statistics 98, 162
Stock Portfolio Evaluation and Analysis 127, 164
T - W
Tax-Free Individual Retirement (IRA) or Keogh Plan 124, 164
Using the RPN Programs on the HP-12C 3
Variable Rate Mortgages 36
Wrap-Around Mortgage 8, 155

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