HP 39gs Master Manual page 176

ROUND(<num>,<dec.pts>)
This function rounds off a supplied number to the specified number of
decimal places (d.p.).
Eg. Round 66.65 to 1 d.p.
Use:
ROUND(66.65,1)
Round 34.56784 to 2 d.p.
Use:
ROUND(34.56784,2)
This function is also capable of rounding off to a specified number of
significant figures (s.f.). To do this, simply put a negative sign on the
second argument.
Round 32345 to the nearest thousand.
Use:
ROUND(32345,-2)
Round 3405.63475 to 6 s.f.
Use:
ROUND(3405.63475,-6)
See also: ,
INT FLOOR
SIGN(<num>)
Another function designed more for programmers, returning a value of
+1, 0 or -1 depending on whether the number supplied is positive,
zero or negative.
Eg. = -1
SIGN(-45)
See also: ,
XPON MANT
Note:
See also
SIGN
= 66.7
= 34.57
= 32000
= 3405.63
, ,
CEILING TRUNCATE
in the Complex group of functions (page 187).
,
FRAC
176