Texas Instruments TI-83 PLUS - Manual (Page 83)

TI-83 Plus Math, Angle, and Test Operations 80
round(
round( returns a number, expression, list, or matrix rounded to #decimals
(  9). If #decimals is omitted, value is rounded to the digits that are
displayed, up to 10 digits.
round( value [ , #decimals ] )
iPart(, fPart(
iPart( (integer part) returns the integer part or parts of real or complex
numbers, expressions, lists, and matrices.
iPart( value )
fPart( (fractional part) returns the fractional part or parts of real or complex
numbers, expressions, lists, and matrices.
fPart( value )