Lesson Topic: The Opposite of a Number

Lesson Objective: I can…Understand that each nonzero

integer has an opposite.Recognize that the number zero

is its own opposite.Understand that since all

counting numbers are positive, there is no need for a plus sign.

What’s the relationship?

Inside and outside Rough and smooth

Empty and full Apart and together

All and none Easy and hard

Question and answer Dangerous and safe

Future and past Wet and dry

Correct and incorrect Entrance and exit

Fast and slow Light and dark Dirty and clean

Alike and different Defeat and victory

Up and down Open and close

Accept and refuse Fiction and nonfiction

Shallow and deep Ancient and modern

Break and fix

Example 1: Every Number has an Opposite

Graph the number 8 and its opposite on the

number line.

What is the opposite of 8?

_______________

How are they related to zero? ___________

What is the opposite of -8?

_______________

Example 2: A Real World ExampleMaria decides to take a walk along Central Avenue to purchase a book at the bookstore. On her way, she passes the Furry Friends Pet Shop and goes in

to look for a new leash for her dog. The Furry Friends Pet Shop is seven blocks west of the

bookstore. After she leaves the bookstore, she heads east for seven blocks and stops at Ray’s Pet Shop to see if she can find a new leash at a better

price. Which locations, if any, are the furthest from Maria while she is at the bookstore?

Determine an appropriate scale and model the situation on a number line. Explain your answer.

What does zero represent in this situation?

Work with your table group

Exercise 1: Make a new number line and graph 9, -2, 4, -7 and their opposites.

Exercise 2: What integer represents the opposite of the situation? Also, explain what zero means in

each situation.

a. 100 feet above sea level.

_______________________

b. 32 degrees below zero.

_________________________

c. A withdrawal of $25.

____________________________

Work with your table groupExercise 3: Make a new number line and graph a credit of $15 and a debit for the same amount

from a bank account. What does zero represent in this situation.

Exercise 4: Make a new number line and graph 20 degrees Celsius below zero and 20 degrees Celsius

above zero. What does zero represent in this situation?

Exercise 5: A proton represents a positive charge. Write an integer to represent 5 protons. __________An electron represents a negative charge. Write an integer to represent 3 electrons. ___________

Lesson Summary…

“Seven blocks to the left” would not be written as “-7 blocks rom the bookstore,” or “-7 units from 0.”

Positive numbers are counting numbers and do not have a sign.

Each nonzero integer, a, has an opposite, –a; -a and a are opposites if they are on opposite sides of zero and the same distance from zero on the number line

Evaluate Your Learning4321

How will you “Sharpen Your Saw”?