If i have 28 sixth graders and 35 seventh graders how many groups can i have with none leftover

Find GCF of 28 and 35:-

28 = 4*8
35 = 5*7     so GCF is 7

So you can have  7 groups of  4 6th graders with 5 7th graders

That is  7 groups  of 9  with none left over.

Answer is 7 groups.

Then just do it (lol)