HP 25

46 The Automatic Memory Stack
For example, you co uld work the problem above by beginning
at the left side
of the equation and simply working through it in
left-to-right order. All problems cannot be solved using left-to-
right
order, however, and the best order for solving any prob-
lem
is to begin with the innermost parentheses and work out-
ward. So, to
solve the problem above:
Press Display
3
3.
~ ~ ==:
mmm 3.00
4 i===;: 4. ===:
El 0.75 Intermediate answer for (3 74).
5 5.
~==== ==:
mmm ~ 5 . = 00 =====i
2 2.
El 2.50
B -1.75
4 4.
~======:
mmm 4.00
3 3.
~ 1 ~ 2 :=; . 0 :=:;: 0 = =:
10.25
3 I 3.
~ :=:==, = =:
mmm I 3.00
.2 13 I 0.213
o I 0.64
El I 16.04
5 I 5.
o ~I =8 '== 0= .2 == 0 ==i
Intermediate answer for (572).
Intermediate answer for
(3 7 4) - (5 7 2).
Intermediate answer for (4 x 3)
Intermediate answer for
(3 7 4) - (5 7 2) + (4 x 3).
Intermediate answer for (3 x .213).
The first number is keyed in.
The final answer.
Constant Arithmetic
You may have noticed that whenever the stack drops becaus e
of a two-number operation (not because of mJ ), the number
in the T-register is reproduced there . This stack operation can
be used to insert a oonstant into a problem.