3.2.2 Numerical Functions
Some numerical functions of real variables.
Extracting integer and fractional parts.
IntegerPart[x] and FractionalPart[x] can be thought of as extracting digits to the left and right of the decimal point. Round[x] is often used for forcing numbers that are close to integers to be exactly integers. Floor[x] and Ceiling[x] often arise in working out how many elements there will be in sequences of numbers with non-integer spacings.
Numerical functions of complex variables.
Finding rational approximations.