HP HP-25 - Page 45

Press Display
34 34is keyed into X.
34is copied into Y.
21 21 writes over the 34 in X.
Now 34 and 21 are sitting vertically in the stack as shown below,
so we can add.
P.oo B
' 0.00
| 34.00
21. Display X
<N+
Press Display
The answer.
The simple, old-fashioned math notation helps explain how to
use your calculator. Both numbers are always positioned in the
stack in the natural order first; then the operation is executed
when the function key is pressed. There are no exceptions to
this rule. Subtraction, multiplication, and division work the
same way. In each case, the data must be in the proper position
before the operation can be performed.
To subtract 21 from 34:
34
—21
Press Display
34 34is keyed into X.
34is copied into Y.
21 21 writes over the 34 in X.
= The answer.
To multiply 34 by 21:
24
x21
Press Display
34
34is
keyed
into
X.
34is
copied
into
Y.
21
(2.
]
21
writes
over
the
34in
X.
(x]
The
answer.