Suppose you have two numbers,

**12**and**18**. 12 = 2*__2__*__3__18 =__2__*__3__*3 The**Greatest Common Factor**(GCF) of these numbers is the largest number that will divide both of them evenly. 12/6 = 2; 18/6 = 3 The GCF of 12 and 18 is**6**= 2*3 The GCF is no larger than the smallest of the numbers. The**Least Common Multiple**(LCM) of these numbers is the smallest number that both of them will divide evenly. 36/12 = 3; 36/18 = 2 The LCM of 12 and 18 is**36**= 2*2*3*3 The LCM is no smaller than the largest of the numbers.*For two numbers*, GCF*LCM = (product of the two numbers) 6*36 = 216 = 12*18 The Greatest Common Factor (GCF) is sometimes called the Greatest Common Divisor (GCD).