Answer:
6
Step-by-step explanation:
a common factor of a number is any number that can fit into that number evenly.
example: A common factor of 4 is 2. 2+2=4 and can fit into 4 evenly. 3 is not a common factor of 4, because when you put 3 into 4 you are left with 1.
the factors of 24 are: 1,2,3,4,6,8,12,24
the factors of 66 are: 1,2,3,6,11,22,33,66
out of these, they both have 1,2,3, and 6 in common
6 is the greatest out of these 4.