HP 39g+ - Manual (Page 160)

11-16 Using mathematical functions
ROUND 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 7.68
ROUND (0.0036757,-3) returns 0.00368
SIGN 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))
Examples
SIGN (–2) returns –1
SIGN((3,4)) returns (.6,.8)
TRUNCATE Truncates value to decimal places. Accepts complex
numbers.
TRUNCATE (value, places)
Example
TRUNCATE(2.3678,2) returns 2.36
XPON Exponent of value.
XPON (value)
Example
XPON(123.4) returns 2
Two-variable statistics
These are functions for use with two-variable statistics.
See “Two-variable” on page 8-14.