Numeric The base class for numbers
Integer The basic integer class, and the basis for the Fixnum class
Float The class for real or floating-point numbers, based on the computer's native capacity to represent double-precision
Fixnum The main integer class, based on what the computer can hold in a native machine word, such as 32 bits or 64 bits, minus 1
Bignum The class of integers outside the range of the basic, native machine word
Math A module that holds math functions (as methods)
Precision A module for approximating the precision of real numbers
Rational A class that represents fractional numbers
Complex A class that represents complex numbers, which extend real numbers with imaginary numbers (x + iy)
Matrix A class for creating mathematical matrixes