"That's not fair!" is a phrase parents often hear. This game takes a mathematical approach to that statement. Introduce probability to your third grader with this fun card game. You'll play a game of chance, then evaluate the odds of winning. Once you've each had a turn, change the game. Use the suggestions at the bottom of the page for ideas. Discuss whether or not the probability of winning changes when you change the rules.
Term to Know:
probability: the chance that a particular outcome will occur
What You Need:
What You Do:
- Among the two participants, select a dealer and a player.
- The dealer shuffles the deck, then places two cards face down on the table.
- The player turns the cards face up. If at least one card is a diamond, the player wins one point. If neither card is a diamond, the dealer wins one point. (Record these scores.)
- Play for ten rounds. Whoever has the most points wins.
- Switch roles and play again.
- Consider the following questions:
Is the game fair? Do the dealer and the player have an equal chance at winning? How do you know?
(Yes, the game is fair, when you think about probability. One out of every four cards in a deck is a diamond. When dealt one card, there is a 25%, or 1/4 chance it is a diamond. When dealt two cards, it is more likely you will find a diamond. The odds of finding one in this case is 50%. Therefore, the player should win about half of the time, and the dealer should win the other half of the time.)
Variations:
- Change the winning suit from diamonds to clubs. Is the game still fair?
- Have the dealer provide only one card each round. Is the game still fair? (Who's more likely to win in this game?)
- Change the winning requirements to finding at least one red card. Is the game fair now?
- Try to come up with different variations on your own, and test them for fairness.
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