GCF(Otherwise known as "Greatest Common Factor")
What if you had 24 girls and 18 boys and you wanted to put them in groups so that they had an equal amount of boys and girls in each group with no one left out. How many groups can you make?
You could find the Greatest Common Factor of 24 and 18


6 x 4


6 x 3

You could have 6 groups, and each group would have 4 girls and 3 boys.
If you are unable to view Youtube, check out this video instead:
Greatest Common Factor - Khan Academy