HP -25 Owner's Handbook Manual page 20

One-Number Functions
To use any one-number function key:
1. Key in the number.
2. Press the function key (or press the applicable prefix key,
then the function key).
For example, to use the one-number function & Jkey, you first
key in the number represented by x, then press the functionkey.
To calculate 1/4, key in 4 (the x-number) and press [£]] .
Press Display
4
&
x 0.25
Now try these other one-number function problems. Remem-
ber, first key in the number, then press the function:
1 —
75 =
/2500 =
10° = (Use the [ key.)
~/3204100 =
log 12.58925411 =
712 -
Two-Number Functions
Two-number functions are functions that must have two num-
bers present in order for the operation to be performed.[+] [-]
and[+]are examples of two-number function keys because you
cannot add, subtract, multiply, or divide unless there are two
numbers present in the calculator. Two-number functions work
the same way as one-number functions—that is, the operation
occurs when the function key is pressed. Therefore, both nuum-
bers must be in the calculator before the function keyis pressed.
When more than one number must be keyed into the calculator
before performing an operation, the key is used to
separate the two numbers.