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Section 4: Programming 2 75
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STEP
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INSTRUCTIONS
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INPUT
DATA/UNITS
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KEYS
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OUTPUT
DATA/UNITS
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1.
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Load program
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2.
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Key in initial dnpmt
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dpo
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dpo
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dp
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3.
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Key in inflation factor (monthly)
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infl. fact
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infl. fact.
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4.
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Key in initial savings
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sav0
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sav0
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sav0
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5.
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Key in monthly savings
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m sav.
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m sav.
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6.
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Key in interest factor (monthly)
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int. fact
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int. fact
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7.
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To see dnpmt for month 1, 2, 3, etc.
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repeatedly press
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dp 1, 2, ...
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8.
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To see savings for month 1, 2, 3, etc.
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repeatedly press
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sav 1, 2, ...
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9.
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To see difference for month 1, press
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sav, -dpl
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to get months 2, 3, etc. repeatedly press
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diff 2, 3, ...
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10.
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To see month at which savings
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overtake dnpmt, press
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mo (diff+)
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11.
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To see difference at any month, enter
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mo.
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diff
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The entire program requires 68 memory locations as shown on the preceding page.
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To save the program, just pass a blank card through the calculator, switched to W/PRGM. Write the new
definitions of keys A, . . . , E on the magnetic card together with the program title. Then
fill out the HP-65 User Instruction Form to remind you how to run the program at a later time. Finally,
if you wish, you can write your instructions on the HP-65 Pocket Instructions Card. You may carry the
magnetic program card in it.
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What we have presented is one possible way to write a program which gives us the required answers.
Doubtless you can think of other ways. You may wish to build your variable entry capability into the
program instead of storing them manually. You may wish to have the labels calculate differently than
we did. Perhaps you can find a way to show what month you are calculating for in labels A and B.
We urge you to try your own way.
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