If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

## MAP Recommended Practice

### Course: MAP Recommended Practice>Unit 35

Lesson 18: Greatest common factor

# Greatest common factor review

Review greatest common factors (GCF) and try some practice problems.

## What is GCF?

GCF stands for greatest common factor. The greatest common factor of two numbers is the greatest number that is a factor of both of them.

## Finding greatest common factor

One way to find the GCF of two (or more!) numbers is to list the factors of each number and find the greatest factor they have in common.

### Example: GCF of $12$‍  and $18$‍

Factors of $12$: $1,2,3,4,6,12$
Factors of $18$: $1,2,3,6,9,18$
$1,2,3$ and $6$ are common factors of $12$ and $18$. Which of these is the greatest?
$6$ is the greatest factor that $12$ and $18$ have in common.
$\text{gcf}\left(12,18\right)=6$

## Practice

Problem 1
What is the greatest common factor of $8$ and $14$?
Another way to say this is:
$\text{gcf}\left(8,14\right)=?$

Want to try more problems like this? Check out this exercise.