Students will learn what Platonic solids are, and why there are exactly five of them. The only prereq is knowing that angles around a point add to 360°. They will also learn a bit about the Mysterium Cosmographicum. I recommend showing students this video.
Next, give your students these challenges:
- Sum and Differences by NRICH
- A Puzzling Cube by NRICH
- Wonky Watches by NRICH
Conclude by leading this investigation:
Celtic Counting (counting, proof)
by MathPickle