In general, a remainder is a quantity ``left over'' after performing a particular algorithm. The term is most commonly used to refer to the number left over when two integers are divided by each other in Integer Division. For example, , with a remainder of 6. Of course in real division, there is no such thing as a remainder since, for example, .
The term remainder is also sometimes applied to the Residue of a Congruence.
See also Division, Integer Division, Residue (Congruence)