How to Find the greatest common factor (GCF)

This video tutorial shows you the proper way to find the GCF, or greatest common factor. While this is not necessary, the video shows a method of drawing a T chart. List both the numbers that you need to find the GCF, then list there factors, including the number 1. Once you display your factors of both numbers it is a clear cut visual of what the GCF is. In the case of the problem on the video the number 4 has factors of: 1, 2, 4 and the number 20 has factors of: 1, 2, 4, 5, 10, and 20. Therefore the highest factor of both numbers (4), would be your greatest common factor.