# Arithmetic/More About Multiplication/The Greatest Common Factor

The Greatest common Factor (GCF) of two whole numbers is the highest number that can be divided by both of the original numbers to get a whole number result.

## Finding the GCF of a number

1. Write down to prime factorization of the two numbers.
2. Find prime factors that are the same.
3. Multiply the same prime factors together for the GCF.

### Example

1. ${\displaystyle 28=2\times 2\times 7}$
${\displaystyle 98=2\times 7\times 7}$
2. Notice that two and seven are used in both the equations?
3. ${\displaystyle 2\times 7=14}$
Therefore, the GCF of 28 and 98 is 14.