 Binary number

A binary representation writes a number in positional notation with radix two and binary digits zero and one. To the left of the binary point the place values are $1,2,4,8,\dots$; to its right they are $1/2,1/4,1/8,\dots$. For example,Binary notation changes the numeral, not the underlying number. The same value is $5.25$ in decimal. A finite binary fraction represents a dyadic rational, while an infinite binary expansion can represent any real number in the unit interval. Storing a finite binary string additionally requires an interpretation such as unsigned interpretation or two's complement.

A binary number is a number expressed in the base-2 numeral system, which uses only two digits: 0 and 1. In contrast to the decimal system (base-10), which uses ten digits (0-9), binary is the foundation of digital computing and electronic systems. Each digit in a binary number is referred to as a "bit.