What is the greatest common factor of 65 and 115?

Answer: 5

Definition: A factor is a divisor - a number that will evenly divide into another number. The greatest common factor of two or more numbers is the largest factor that the numbers have in common.


One way to determine the common factors and greatest common factor is to find all the factors of the numbers and compare them.

The factors of 65 are 1, 5, 13, and 65.

The factors of 115 are 1, 5, 23, and 115.

The common factors are 1 and 5. Therefore, the greatest common factor is 5.
The GCF is 5.