List the factors for 15 and List the factors for 20 then list the Greatest Common Factor of 15 and 20.
The factors of 15 are: 1, 3, 5, 15
The factors of 20 are: 1, 2, 4, 5, 10, 20
The greatest common factor of 15 and 20 is 5.
The factors of 20 are: 1, 2, 4, 5, 10, 20
The greatest common factor of 15 and 20 is 5.