Chain Arithmetic - HP 25 Owner's Handbook Manual

42 The Automatic Memory Stack
To divide 34 by 21:
Press
34
Imim
21
El
Display
34.
I
34.00
I
21 .
I
1.62
34
21
34 is keyed into X.
34 is copied into Y .
21 writes over the 34 in X .
The answer.
Chain Arithmetic
You've already learned how to key numbers into the calculator
and perform calculations with them. In each case you first
needed to position the numbers in the stack manually using the
Imim
key. However, the stack also performs many move-
ments automatically. These automatic movements add to its
computing efficiency and ease of use, and it is these movements
that automatically store intermediate results. The stack auto-
matically "lifts" every calculated number in the stack when a
new number is keyed in because it
knolVs
that after it completes
a calculation, any new digits you key in are a part of a new num-
ber. Also, the stack automatically "drops" when you perform a
two-number operation. For example, calculate 16
+
30
+
11
+
17
=
?
Note: If you press mEl first , you will begin with zeros in all
of the stack registers , as the example below .
Press Stack Contents
T
0.00
16
Z
0.00
Y
0.00
16 is keyed into the displayed
X
16.
X-register.
T
0.00
Z
0.00
Y
16.00
X
16.00
16 is copied into Y.