How can a cube be cut into 20 cubes (not necessarily the same size)?
With Rubik's, you can also get 6 cubes: 8,8,8,1,1,1
and 13 cubes: 8,8,1,1,1,1,1,1,1,1,1,1,1
You can easily "make up" these questions; like:
"How can a cube be cut into 5 cubes (not necessarily the same size)?"
First, divide the cube in 64 smaller cubes;
stick 27 together twice, 8 together once; you have: 27,27,8,1,1