# Common factor

A common factor is a factor that two or more numbers share.

Example

Factors of 10: 1, 2, 5, and 10

Factors of 20: 1, 2, 4, 5, 10, and 20

Common factors of 10 and 20 include 1, 2, 5, and 10

The greatest common factor of 10 and 20 is 10.

Also called common divisor.

See also greatest common factor.