A cube is made of chocolate, but the outside is covered with white icing. If the cube is cut into 125 smaller cubes of exactly the same size, how many cubes will have at least 2 sides with white icing?
the cube would be 5 wee cubes long, 5 wide and 5 high.
There's the 8 corners with 3 iced sides each.
Along each edge, there's then 3 (length of 5, minus 2 corners) cubes with 2 iced faces.
A cube has 12 of these edges.