Cutting the Cake

Fair division without a referee

An interactive lesson with 7 steps, about 6 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Cut-and-choose gives two people an envy-free division.
• Each person gets at least their fair share by their own valuation.
• Envy-free division for three or more people needs cleverer protocols.

Steps

1. I cut, you choose
2. Different tastes
3. The cherry end
4. Three people
5. The moving knife
6. Envy-free
7. Cutting by your own values