7th Grade Math

Multi-Part

Lesson (^3) Predictions
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Multi-Part
Lesson 3
Get ConnectED
GLE 0706.5.5
Understand and apply basic
concepts of probability.
SPI 0706.5.4 Use theoretical
probability to make
predictions. Also addresses
GLE 0706.1.3, GLE 0706.1.8.
466 Probability and Predictions
Fair and Unfair Games
Mathematically speaking, a two-player game is fair if each player has
an equal chance of winning. A game is unfair if there is not such a
chance. In this activity, you will analyze two simple games and
determine whether each game is fair or unfair.
In a counter-toss game, players toss
three two-color counters. The winner
of each game is determined by how
many counters land with either the red
or yellow side facing up. Play this
game with a partner.
Player 1 tosses the counters. If 2 or 3 counters land
red-side up, Player 1 wins. If 2 or 3 counters land
yellow-side up, Player 2 wins. Record the results in a
table like the one shown below. Place a check in the
winner’s column for each game.
Game
1
2
Player 1 Player 2
Player 2 then tosses the counters and the results are
recorded.
Continue alternating the tosses until each player has
tossed the counters 10 times.
the Results

1. Make an organized list of all the possible outcomes resulting from
   one toss of the 3 counters.


2. Calculate the theoretical probability of each player winning. Write
   each probability as a fraction and as a percent.


3. MAKE A CONJECTURE Based on the theoretical probabilities of each
   player winning, is this a fair or unfair game? Explain your
   reasoning.


4. Calculate the experimental probability of each player winning.
   Write each probability as a fraction and as a percent.

Main Idea

Use experimental and

theoretical probabilities

to decide whether a

game is fair or unfair.

Vocabulary

fair game

unfair game

466_476_C08_L3_895130.indd 466 12/29/09 1:32 PM