HP 20B User Manual page 29

Mathematical Calculations
=
To find a percentage of a given number, enter the number and multiply it by the desired percentage, followed by . For
200*25%=
to return a result of 50 .
example, to find 25% of 200, press
+ -
To add or subtract a percentage of a number, enter the first number, followed by or and the percentage followed
% = 50+10%=
.
by Finish your calculation with . For example, to add 10% to 50, press to
return a result of 55 .
%
In RPN mode, the key calculates x % of the number on Level 2 of the stack, when x is the number on Level 1 of the
stack. It does not modify the number on Level 2 of the stack, and thus allows you to perform addition or subtraction after
%
pressing to add or subtract x % from the number.
200I25% -
returns 50 , but 200 is still on Level 2 of the stack, and pressing
For example,
returns 150 , or 200-25%.
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