Arbitrary-precision arithmetic

Summary

Arbitrary-precision arithmetic computes with numbers whose number of digits is limited only by the memory of the computer, not by a fixed hardware format. Integers and rational numbers can then be handled exactly, and real numbers with as many correct digits as one asks for. Unlike fixed-size floating-point arithmetic, each operation costs more as the numbers grow, so fast multiplication algorithms matter. It is used in computer algebra, number theory, cryptography and to check numerical results with higher precision.