Skip to main content
Slide - 1
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved
Interactive Algebra Foundations
Chapter 2
Integers and
Introduction to
Solving
Equations
Slide - 2
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved
Section 2.1 Introduction to Integers
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 3
Objectives
A. Represent Real-Life Situations with
Integers.
B. Graph Integers on a Number Line.
C. Compare Integers.
D. Find the Absolute Value of a Number.
E. Find the Opposite of a Number.
F. Read Bar Graphs Containing Integers.
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 4
Positive and Negative Numbers
Numbers greater than 0 are called positive
numbers. Numbers less than 0 are called negative
numbers.
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 5
Negative and Positive Numbers
−3 indicates “negative three.”
3 and + 3 both indicate “positive three.”
The number 0 is neither positive nor negative.
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 6
Example 1
The world’s deepest bat colony spends each
winter in a New York zinc mine at a depth of
3805 feet. Represent this position with an
integer. (Source: Guinness Book of World
Records.)
−3805
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 7
Comparing Integers
We compare integers just as we compare
whole numbers. For any two numbers
graphed on a number line, the number to the
right is the greater number and the number
to the left is the smaller number.

means “is
less than”

means “is
greater than”
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 8
Graphs of Integers
The graph of −5 is to the left of −3, so −5 is less
than −3, written as −5 < −3.
We can also write −3 > −5.
Since −3 is to the right of −5,
−3 is greater than −5.
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 9
Example 3
Insert < or > between each pair of numbers to
make a true statement.
a. 6 3
 
b.
7
0
8


c. 3.6 4.2
 

Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 10
Absolute Value
The absolute value of a number is the
number’s distance from 0 on the number line.
The symbol for absolute value is .
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 11
Example 4
Simplify.
a. 8
 = 8 because −8 is 8 units from 0.
b. 9 = 9 because 9 is 9 units from 0.
c. 15
 = 15 because −15 is 15 units from 0.
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 12
Helpful Hint (1 of 2)
Since the absolute value of a number is that
number’s distance from 0, the absolute value of a
number is always 0 or positive. It is never negative.
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 13
Opposite Numbers (1 of 2)
Two numbers that are the same distance
from 0 on the number line but are on the
opposite sides of 0 are called opposites.
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 14
Opposite Numbers (2 of 2)
5 is the opposite of −5 and −5 is the opposite
of 5.
The opposite of 4 is −4 is written as
4
(4)
 
The opposite of −4 is 4 is written as
 
4 4
  
If a is a number, then .
( )
  
a a
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 15
Helpful Hint (2 of 2)
Remember that 0 is neither positive nor
negative. Therefore, the opposite of 0 is 0.
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 16
Example 5
Find the opposite of each number.
a. 14
The opposite of 14 is −14.
b. −3
The opposite of −3 is ( )
3 3.
  or
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 17
Example 6
Simplify.
a. 5
( )
 
The opposite of −5 is 5.
b. 8
 
The opposite of the absolute value of −8 is the
opposite of 8, or −8.
c. 3

The opposite of the absolute value of 3 is the
opposite of 3, or −3.
Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 18
Example 7
Evaluate  x if x = −6.
Replace x with −6; then simplify.
6
  
x
6

Copyright © 2020 and 2016 Pearson Education, Inc. All Rights Reserved Slide - 19
Example 8
Which planet has the highest average daytime
surface temperature?
Venus
Source: The World Almanac, 2009
* For some planets, the temperature given is the temperature where the
atmospheric pressure equals 1 Earth atmosphere.