HP 33s - Manual (Page 60)

3–4 Storing Data into Variables
Clearing Variables
Variables' values are retained by Continuous Memory until you replace them or
clear them. Clearing a variable stores a zero there; a value of zero takes no
memory.
To clear a single variable:
Store zero in it: Press 0 I variable.
To clear selected variables:
1. Press { Y {# } and use š or ™ to display the variable.
2. Press { c .
3. Press ‡ to cancel the catalog.
To clear all variables at once:
Press { c {# }.
Arithmetic with Stored Variables
Storage arithmetic and recall arithmetic allow you to do calculations with a
number stored in a variable without recalling the variable into the stack. A
calculation uses one number from the X–register and one number from the
specified variable.
Storage Arithmetic
Storage arithmetic uses I › , I , I z , or I q to do
arithmetic in the variable itself and to store the result there. It uses the value in the
X–register and does not affect the stack.
New value of variable = Previous value of variable {+, –, Ч, ч} x.
For example, suppose you want to reduce the value in A(15) by the number in the
X–register (3, displayed). Press
I A. Now A = 12, while 3 is still in the
display.