A factor is a natural number that can be multiplied by another natural number to get a value. The greatest common factor refers to when one compares the factors of two numbers, the largest natural number that both numbers have in common is the number's greatest common factor.
In the case of (
) and (
), the greatest common factor is (
) because there are no factors of (
) that are larger than it. No number can have a factor larger than itself. Since (
) is also a factor of (
) it is the greatest common factor of the two numbers.