The greatest common factor of 42 and 72 is 6.
6 times 7 is 42. 6 times 12 is 72. There is no greater factor for both numbers except for 6.
Hope this helps!
Consider the factors of both numbers
factors of 42 are 1, 2, 3, 6, 7, 14, 21, 42
factors of 72 are 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72
common factors are 1, 2, 3, 6
the gcf = 6
