This is documentation for Mathematica 8, which was
based on an earlier version of the Wolfram Language.
 MATHEMATICA GUIDE Functions »| More About »|Tutorials »
Numerical Functions
Throughout Mathematica there is support not only for approximate real numbers, but also for exact numbers represented in algebraic or symbolic form. Functions like Floor, IntegerPart, and Max are all in effect set up to "prove theorems"—often using original algorithms developed at Wolfram Research—to give values with exact inputs.

Min, Max minimum or maximum of numbers or lists
Abs absolute value
Sign sign (-1, 0, +1)

Clip clip to between -1 and +1 or other limits
Rescale rescale to run between 0 and 1
Chop chop small values to 0

Unitize 0 for , and 1 otherwise
UnitStep 0 for , and 1 for
Piecewise general piecewise function
Boole 1 for True, 0 for False
DiscreteIndicator indicator function for a discrete set

Less(< ▪ Greater(> ▪ LessEqual(<= ▪ GreaterEqual (>=)

IntegerQ test whether an expression is an integer
TUTORIALS