You have a 10x10x10 inch cube that is made up of little 1x1x1 inch cubes. You paint the outside of the big rube red. How many little cubes have paint on at least one of their sides?
we know that 9 by 9 by 9 of them are inside or 729 the 10 by 10 by 10 one has 1000 cubes the ones that are inside are the ones that are not covered total-inside=painted 1000-729=271
