Greatest Common Factors

A greatest common factor is the largest number that divides evenly into each of the numbers. This is always used with two numbers.

The greatest common factor of 36 and 54 is 18. To find the greatest common factor, list out all the factors of both numbers.

For Example:

36: 1, 2, 3, 4, 6, 9, 12,18, 36.

54: 1, 2, 3, 6, 9, 18, 27, 54.

The common factors are: 1, 2, 3, 6, 9, and 18, and the largest one is 18. 

The common factors are numbers that both numbers are divisible by.

If you know what the greatest common factor is, you can simplify fractions. 

For Example:

12 & 36

Common Factors: 1, 2, 3, and 6.

12/6 = 2

36/6 = 5

REDUCED FRACTION: 2/5

You might also see the Greatest Common Factor listed as GCF, HCF (Highest Common Factor), or Greatest Common Denominator. 

For More Information: http://www.mathsisfun.com/greatest-common-factor.html