Avoid repeating the question as it can be perplexing.
Given 100 cookies and 20 brownies,
What is the highest number you can divide them equally by?
To find the greatest common factor,
Factor them:
100 = 2*2*5*5
20 = 2*2*5
Thus, the greatest common factor, which is shared between them, is 2*2*5 or 20.
Calculating further, 100/20=5
20/20=1
This means there are 20 groups, each containing 5 cookies and 1 brownie.
20 groups