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### Course: 6th grade>Unit 6

Lesson 11: 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.
Want to learn more about greatest common factors? Check out this video.

### 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.

## Want to join the conversation?

• are factor and divisor the same thing?
• factors are for multiplication.
divisors are for division.
• What is a quicker way to do this?
• A very quick way is to use the cake/ladder method.
• as my fortune cookie once said "never let things that dont matter distract you" :)
• this is comfusing can you help
• so just list all its divisors and see the biggest one that divides both of them.
(1 vote)
• I'm a little bit confused but I'm confident that my scores going to be good Hope me luck (<0>_<0>)
• How Do You do this I am so confused on it I only got 3 out of 7 right