To get started using this method of finding the Greatest Common Factor of [n] and [m], we should first find and list all the factors of each number. You can see how this is done by looking at the “Factors of” articles that are linked to below.
Let’s take a look at the factors for each of these numbers, 1 and 120:
Factors of 1: 1
Factors of 120: 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 30, 40, 60, 120
When you compare the two lists of factors, you can see that the only common factor is 1. So, in this case, the GCF of 1 and 120 is 1.