#### Greatest Common Divisor (or Factor)

The greatest common factor, or GCF, is the greatest factor that divides two or more numbers. To find the GCF of two numbers: List the prime factors of each number. Multiply those factors both numbers have in common. If there are no common prime factors, the GCF is 1.

Example: To find the GCF of 24 and 32

Prime factors of 24 : **2, 2, 2,** 3

Prime factors of 32 : **2, 2, 2,** 2, 2

GCF is **2 x 2 x 2** which is equal to **8**.