Seventh Grade · Math · week 35

Carnival-game design project

Design a simple game of chance, compute the probability of winning, and evaluate whether the game feels fairly balanced.

This project puts the whole probability toolkit to work: design your own simple carnival-style game using a spinner, dice, or a bag of marbles, then calculate exactly how likely a player is to win.

A game does not have to give every player a 50-50 chance to feel fun and fair -- carnival games are usually designed so the house wins more often, while still offering an exciting, genuinely possible prize. Thinking about probability alongside prize value is exactly how real game designers work.

📋 For the teacher
Teach it (10–15 min):
  • Let them choose the tool for their game -- a spinner, dice, or a marble bag -- and design the winning rule themselves.
  • Have them compute the exact probability of winning their own game before deciding whether the prizes feel balanced.
  • Introduce the idea of expected outcomes over MANY plays (like 100 or 200), not just one single play, to reason about fairness.
  • Let this spark a real conversation: real carnival and arcade games are deliberately designed with the odds figured out in advance.
Talk about it:
  • How did you decide on the probability of winning your game?
  • What would happen to your game's balance if you made the winning rule easier?
  • Why might a game designer want the odds to favor the house, while still keeping the game fun?

Mastery looks like: They design a game of chance, correctly compute its winning probability, and reason about whether its prizes are balanced against that probability.

Common stumbles: Designing a game without actually calculating its true probability of winning; ignoring prize value when judging whether a game feels balanced.

Homework for this lessonType it, write it with a stylus, or print it for pencil & paper.open →
Records attendance + 15 min of Math for this learner.
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