Question

how do you place seven small circles into three big circles that each big circles contain four small circles​

Answer 1

You overlap the big circles so some small circles are shared. Let's call the big circles A, B and C. Arrange them so all three overlap in the center, you would also then have overlaps between just A and B, between B and C and between C and A. Place a small circle in the overlap between all three; each big circle now has one small circle. Place two small circles in the overlap between A and B; now circles A and B have three small circles each, Place a small circle in A only giving A four circles, one in B only giving B four circles and two in C giving C four circles This puzzle tests your ability to realize that the solution could be asymmetric.

This is probably one of the reasons I aced the Mensa tests and Clifford probably didn't with his "simple math" nor whomever thumbed him up.