Make an organized list with the factors for each number.
18
Practice makes perfect
The greatest common factor (GCF) is the greatest number that is a factor of two or more numbers.
To find the GCF, we will make an organized list of the factors for each number.
Given number
Common factors
18
1, 2, 3, 6, 9, and 18
54
1, 2, 3, 6, 9, 18, 27, and 54
72
1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, and 72
In the table we can see that the greatest common factor (GCF) is 18 because it is the greatest factor that 18, 54, and 72 share.
