# What Is the Greatest Common Factor?

## What Is the Greatest Common Factor?

The greatest common factor is the largest factor that is common to two or more numbers.

## Understanding the Greatest Common Factor

The numbers that multiply together to make another number are its factors.

**2** is a factor of 4 because **2** × **2** = 4:

**2** and **3** are factors of 6 because **2** × **3** = 6:

The greatest common factor is the largest number that is a factor for both numbers.

In our example, **2** is the greatest common factor.

Another way of thinking about a factor is as a number which divides exactly into another number.

**2** is the largest number that divides exactly into 4 and 6.

4 ÷ **2** = 2

6 ÷ **2** = 3