Find the gcf of 54, 72 and 81

The greatest common factor of 54, 72, and 81 is: 9

To find the GCF, we must list factors of the three numbers given. Always remember, the minimum of when to stop listing factors is when your reach the number given.

Factors of 54: 1, 2, 3, 6, 9, 18, 27, 54
Factors of 72: 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72
Factors of 81: 1, 3, 9, 27, 81.

Now that we have the common factors listed, which numbers are common between the three? 1, 3, and 9 are the common numbers of the three numbers, but since we are looking for the greatest common factor, the answer will be 9 since it is the greatest of the common factors.