HP HP-67

68 The Automatic Memory Stack
In the above example, when the first £ is pressed, followed by
@ (tsTx), the contents of the stack and LAST X registers are
changed...
...fromthis... ...tothis... ...to this.
T 0.00 T 0.00 T [0.00
Z 0.00 Z 000 Z 0.00
Y 12.00 Y 0.00 Y 3.80
X |3157 B X [3.80 0 X 3.16
S LasTx _/
This makes possible the correction illustrated in the example above.
Recovering a Number for Calculation
The LAST X register is useful in calculations where a number occurs
more than once. By recovering a number using (LSTx], you do not
have to key that number into the calculator again.
Example: Calculate
7.32 + 3.650112331
3.650112331
Press Display
7.32
ENED
3.650112331
Intermediate answer.
0 Gx Recalls 3.650112331 to
X-register.
8 3.01 The answer.
Constant Arithmetic
You may have noticed that whenever the stack drops because of a
two-number operation (not because of (R¥)), the number in the
T-register is reproduced there. This stack operation can be used to
insert a constant into a problem.