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General Operating Instructions
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Special Operations
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If you followed instructions and read the Introduction,
you have already seen a typical example of the scope and power of the
HP-80. Just in case you’re underwhelmed, and still
think it’s just another calculator, here’s an additional example:
Suppose you invested $50,000 and were guaranteed a return of $10,000
each year for seven years. Now, try to figure the annual rate
of return by some ordinary method. Then do it on the HP-80 as follows,
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| | Enter: | | | See Displayed: | | |
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% annual rate of return
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If you want to verify this problem,
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| | Enter: | | | See Displayed: | | |
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7  n RCL (9.20) i 10000 PMT PV | | | | $ |
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present value
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The HP-80 has built-in logic that enables you to perform two broad classes of complex functions: (1) financial and (2p) interactive.
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Certain keys are used to perform these special functions. Some functions
use keys from both the financial and interactive classifications—as
well as keys from the basic
classification. For example, discounted cash flow analysis and
accumulated interest problems use both financial and interactive keys.
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Financial Functions
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Financial functions are used primarily in investment and loan applications (simple interest, compound interest, annuities and bond problems).
These problems require three
known values to get a fourth value. After each value is entered, it is
loaded by pressing the applicable top-row key that identifies the value.
The fourth value is obtained by pressing the top-row key
representing the unknown value. Interest is always an annual rate
unless specified to the contrary.
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The key set associated with these functions is illustrated in Fig. 2. (note that SAVE is not used to load values). You’ll probably be surprised to learn that the
five keys in Figure 2 represent 17 functions and replace all the compound interest, discount, bond and annuity tables commonly in use.
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