HP HP-18C - Using Parentheses in Calculations; Recalling Numbers to the Calculator Line; Using the History Stack

Using Parentheses in Calculations
Use parentheses when you need to postpone calculating an interme-
diate result until you've entered more numbers . For example, suppose
you want to calculate:
30
x 9
85 - 12
If you were to key in 30885 G, the HP-18C would calculate the
intermediate result, 0.35. However, that's not what you want . To de-
lay the division until you've subtracted 12, use parentheses:
Keys: Display: Description:
30 8ITJ 85 G
30.00.;.(85.00-
No calculation is done .
12 OJ
30.00.;.73.00 Calculates 85 - 12.
09
0.41x9
Calculates 30 / 73.
0
3.70
Calculates 0.41 x 9.
Recalling Numbers to the Calculator Line
Sometimes, you may want to include the result of a previous calcula-
tion in a new calculation. There are several ways to reuse numbers.
Using the History Stack
When you start a new operation on the calculator line, the previous
contents moves to line 2, and eventually, to line 1. Lines 1, 2, and 3
display three lines of the history stack-a record of activities.
2: Arithmetic 37