A three-inch blue cube is cut up into 27 little cubes. The inside of the cube is white. How many of the 27 little cubes have one blue face? Two? Three? More than three?
One blue face: 6
Two blue faces: 12
Three blue faces: 8
More than three: 0
Let’s see: 6 + 12 + 8 = 26. Are we missing a cube?