♥ Common factors of 9:
1, 3, 9
♥ Common factors of 18 are:
1, 2, 3, 6, 9, 18
The Greatest Common Factor:
=9
You can find the greatest common factor by looking at the highest point in each factor.
The highest in 9 is 9 and 9 is in 18 and that is the highest of 9 therefore its the highest total.