HP HP-21 - Chain Arithmetic

To divide 34 by 21:
34
21
Press Display
34 34 is keyed into X.
34 is copied into Y.
21 21 writes over the 34 in X.
(=] The answer.
Chain Arithmetic
You’ve already learned how to enter numbers into the calcu-
lator and perform calculations with them. In each case you
first needed to position the numbers in the stack manually using
the key. However, the stack also performs many
movements automatically. It’s these automatic movements
that give it tremendous computing efficiency and ease of use,
and it’s these movements that automatically store intermediate
results. The stack automatically ‘‘lifts’’ every calculated
number in the stack when a new number is keyed in because
it knows when it completes a calculation that any new digits
you key in are a part of a new number. Also, the stack auto-
matically ‘‘drops’’ when you perform an operation. For
example, calculate 16 + 30 + 11 + 17 = ?
Note: Pressl[cr]to insure that the stack initially
contains all zeros.
Press Stack Contents
~0.00
0.00 16 is keyed into the displayed
0.00 X-register.
16.
16
0.00
0.00
16.00
16.00
16 is copied into Y.
X <
N=-
X~<N-