HP 25 User Manual

40 The Automatic Memory Stack
One-Number Functions
and the Stack
One-number function s execute upon the numb er in the X-
register only , and the content s of the Y -, Z-, and T -registers
are unaffected when a one - number function key is pre ss ed.
For example , with numb ers positioned in the s tack as in the
earlier ex a mple , pressing the [ill keys ch ang es the stack
contents ...
from this .. .
to
this .
T
0.00
l
T
1
0
.00
z
0.00
Z
f---
I
lO. oo
y
314.32 Y
314 . 32 ~
X
1-- 689 ~ Di s pl ay
X
1 26 . 2 ~ J
Displa y
The one - number function execute s up on only the numb er in the
displayed X-regis ter , and the a nswer write s over the number
that wa s in the X -regis ter. No other register is aff e ct ed by a one-
number function .
Two-Number Functions
and the Stack
Hewlett- Pack ard calcul a tor s do arithmetic by positioning the
number s in the st a ck the same way y ou would on pap er. F or
instance , ifyou 'wa nted to add 34 and 21 you would writ e 34 on a
piec e of paper and then write 21 underneath it, like this:
34
21
and then you would add, like this:
34
+
21
55
Number s ar e position ed th e same wa y in th e HP - 25 . H er e 's
how it is don e. (If you cl ea r th e pr evious numb er e nt ries
first by pressing a ~ th e numb ers in th e st ack will co r-
respond to those s hown in th e ex ampl e below .)

HP 25 Specifications

General

Power Source	Rechargeable battery pack
Programming Steps	49
Release Year	1975
Functions	Trigonometric, logarithmic, statistical
Type	Scientific
Dimensions	148 x 80 x 14 mm