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.