So the GCF of both 8 and 20 is 4 because 2 x 4 is 8 and 5 x 4 is 20 4 is the greatest number that can go into them. To do distributive property you put the GCF outside the parentheses like this: 4( for the inside you just put the multiplication you would do 4x2 is 8 and 4x5 is 20 4(2 + 5) = 8 + 20
