A binary digit is one of the two digits 0 and 1 used in the binary numeral system. A binary digit is also called a bit.
In a binary expansion, a binary digit 
in a position with place value 
contributes 
to the represented number, where
is an integer.
For example,
 |
This binary expansion contains four binary digits. The leftmost binary digit 1 contributes 4, while the binary digit 1 to the right
of the point contributes 
.
Unlike a decimal digit, which has ten possible values, a binary digit has only two possible values. Strings of binary digits represent numbers by positional notation and are also used to encode information in computers, where their length is measured in bits.
