[
  "The 12-cm cube cuts into 64 small 3-cm cubes. Edge cubes (not corners) have exactly 2 painted faces.",
  "Each of the 12 edges has 4 cubes; remove the 2 corners leaves 2 per edge. 12 x 2 = 24 cubes.",
  "Each small cube is 27 cubic cm. 24 x 27 = 648 cubic cm total."
]