What is the greatest common factor of 400 and 500?

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 both 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 400 are 1, 2, 4, 5, 8, 10, 16, 20, 25, 40, 50, 80, 100, 200, and 400.

The factors of 500 are 1, 2, 4, 5, 10, 20, 25, 50, 100, 125, 250, and 500.

The common factors are 1, 2, 4, 5, 10, 20, 25, 50, and 100. Therefore, the greatest common factor is 100.