Make a cube out of straws and have a go at this practical challenge.
Reasoning about the number of matches needed to build squares that share their sides.
How can the same pieces of the tangram make this bowl before and after it was chipped? Use the interactivity to try and work out what is going on!
Swap the stars with the moons, using only knights' moves (as on a chess board).
What's the smallest number of moves possible? (Only once piece can occupy a single square at a time.)