The GCD is also known as the greatest common factor (GCF), highest common factor (HCF) , greatest common measure (GCM), or highest common divisor.

Example: the Gcd for 12 and 80 is 4.

In mathematics, the greatest common divisor (gcd) of two or more numbers / integers, when at least one of them is different from zero, is the largest positive integer that divides the numbers without a remainder.

The greatest common divisor is useful for reducing fractions to be in lowest terms.