Well, you see the yellow colored "face" Think of it as area. So we got a smaller square next to it right...just ignore it and look at the yellow square. So, how do you find the area? Length times width right? So, since this cube has 4 inches all over it, what do you think you have to do if a square has equal sides/measurements. You multiply 4*4, which is 16! NOTE: It is NOT asking for volume! Hope this helps!