Students will see the missing square puzzle, the purpose of which, is to demonstrate that visual proofs must be scrutinized.

Next, give your students these challenges:

- A geometry question that teachers love to ask by MindYourDecisions
- Halving by NRICH
- 2018 Math Kangaroo Levels 7-8 Problem #23 by STEM4all

Conclude by leading this investigation:

The Broken Sword (addition, division, mini-mathematical universe)

by MathPickle