Number Theory
Basic

Even and Odd Numbers

Every integer is either even or odd.

Formula

n=2k  (even),n=2k+1  (odd)n = 2k \;(\text{even}), \quad n = 2k+1 \;(\text{odd})

Variables

nInteger
kInteger

Example

10 = 2·5 is even; 11 = 2·5 + 1 is odd.

Did You Know?

Parity — evenness or oddness — is the simplest error-detecting check and appears throughout computer science.

parityevenodd