7th Grade Math

Multi-Part

Lesson (^1) Probability
PART A BCD
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Multi-Part
Lesson 1
Get ConnectED
GLE 0706.5.5
Understand and apply basic
concepts of probability. Also
addresses GLE 0706.1.1,
GLE 0706.1.7.
Main Idea
Find the probability of
a simple event.
Vocabulary
outcome
simple event
probability
random
complementary event
geometric probability
Probability and Simple Events
FOOD A cheesecake has four equal slices
of each type as shown.

1. What fraction of the cheesecake

Cheesecake

original raspberry

chocolate turtle

is chocolate? Write in simplest form.

2. Suppose your friend gives you the
   first piece of cheesecake without
   asking which type you prefer. Are
   your chances of getting original the
   same as getting raspberry? Explain.

An outcome is any one of the possible results of an action. A simple

event has one outcome or a collection of outcomes. For example,

getting a piece of chocolate cheesecake is a simple event. The chance

of that event happening is called its probability.

Probability

Words If all outcomes are equally likely, the probability of a simple

event is a ratio that compares the number of favorable

outcomes to the number of possible outcomes.

Symbols P(event) = ___number of favorable outcomes

number of possible outcomes

Find Probability

What is the probability of rolling an even number

on a number cube?

P(even number) =

even numbers possible

__

total numbers possible

= _ 63 or _^12

The probability of rolling an even number is _^12 , 0.5, or 50%.

Use a number cube to find the probability of each event. Write

as a fraction in simplest form, a decimal, and a percent.

a. P(odd number) b. P(5 or 6) c. P(prime number)

Lesson 1A Probability 429

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