Brian from Riverdale thought about the 3 by 3 by 3 cube carefully. He said:There are 12 cubes that have only 2 faces painted. They are the middle cube along each edge.
Rebecca from St John the Baptist School, Findon, explained how she went about the problem:I found the answer by first drawing the cube on a piece of paper, then making it real in my head.
Well done, Rebecca! When you're picturing something in your head, as you were, we can also say you are "visualising". The Maths Group from Stourport Primary saw it in a slightly different, but equally good, way. They wrote:Curt noticed that there are 4 of these little cubes on each of the 3 layers of the big cube.
Very well done. Has anybody investigated a 4 by 4 by 4 cube? Or even bigger cubes?
Let us know if you do.