7.11 Probability, Fractions, and Spinners

Mental Math There are 5 red and 5 blue blocks in a bag. What are the chances of picking a red block? What are the chances of picking a blue block? What are the chances of picking a green block?

Mental Math There are 3 red, 1 blue and 2 green blocks in a bag. What are the chances of picking a red block? What are the chances of picking a blue block? What are the chances of picking a green block?

Mental Math There are 25 red, 25 blue, 20 green, and 30 yellow blocks in a bag. What are the chances of picking a red or a blue block? What are the chances of picking a green block? What are the chances of picking a yellow block?

Discuss with a Partner Think of a game you like to play in which the players roll dice. How are dice used in the game? What are other devices used for the same purposes as dice?

Fairness A fair die or a fair spinner must have an equal chance of landing on a particular number or part of the circle. For example, if a die is weighted to land on a specific number, it is unfair. Also, if a spinner is on an uneven surface, the results of the spin are altered, making it unfair.

Experiment 1

Experiment 2

Summarize your Results What was the likelihood of landing on a particular color? Look at Problem 2c – the word EXPECT means that one would expect the paper clip to land on red about 100 times. This does not mean that it will do so exactly 100 times. In fact, it probably won’t land on red exactly 100 times.

Spinner Designers A board game company has hired you to design a new spinner for their latest game. Your instructions are given on page 211. Work with a partner to create the spinners requested.