If Isaac has 21 green marbles and 7 blue marbles and wants to make equal groups with none left over, what is the greatest number of groups he can make?
The greatest number of groups would probably be 7 because: 21+7 = 28 28: 1, 2, 4, 7, 14 28/2 = 14 Half of 28 is 14 which means that each group will have 2 marbles. I am not sure if I'm correct, but I hope this helps! :)