Answer: The greatest common factor (GCF) of a set of numbers is the largest factor that all the numbers share.
Explanation:
For example: If the question is ' What is the greatest common factor of 18 and 36?'
Find the numbers when multiplied together give you 18 or 36.
Let's start with 18: 1x18=18
2x9=18
3x6=18
Let's do 36 now: 1x36=36
2x18=36
3x12=36
4x9=36
6x6=36
The numbers underlined are the common factors of 18 and 36. (1,2,3,6,9,18)
Out of 1,2,3,6,9 and 18 ,which are the common factors, which number is the greatest?
18 is the greatest number among the rest of the common factors, thus, it is the greatest common factor.