HP 40gs User Manual page 170

%
%CHANGE
%TOTAL
RAD→DEG
ROUND
SIGN
13-16
Example
9 MOD 4 returns 1
x percent of y; that is, x/100*y.
%(x, y)
Example
%(20,50) returns 10
Percent change from x to y, that is, 100(y–x)/x.
%CHANGE(x, y)
Example
%CHANGE(20,50) returns 150
Percent total : (100)y/x. What percentage of x, is y.
%TOTAL(x, y)
Example
%TOTAL(20,50) returns 250
Radians to degrees. Converts value from radians to
degrees.
RAD→DEG (value)
Example
RAD→DEG(π) returns 180
Rounds value to decimal places. Accepts complex
numbers.
ROUND(value, places)
Round can also round to a number of significant digits as
showed in example 2.
Examples
ROUND(7.8676,2) returns 7.87
ROUND (0.0036757,-3) returns 0.00368
Sign of value. If positive, the result is 1. If negative, –1. If
zero, result is zero. For a complex number, this is the unit
vector in the direction of the number.
SIGN(value)
SIGN((x, y))
Using mathematical functions