Course 2
2-1 Integers
Theopposite of a number is the same
distance from 0 on a number line as the
original number, but on the other side
of 0. Zero is its own opposite.
1 2 3 4 5
• •
–5–4–3–2–1 0
–4 and 4 are opposites
–4 4
Negative integers Positive integers
0 is neither positive
nor negative
7.
Course 2
2-1 Integers
Theintegers are the set of whole
numbers and their opposites. By using
integers, you can express elevations
above, below, and at sea level. Sea level
has an elevation of 0 feet.
The whole numbers are the counting
numbers and zero: 0, 1, 2, 3, . . . .
Remember!
8.
Course 2
2-1 Integers
Graphthe integer 7 and its opposite on a
number line.
Additional Example 1: Graphing Integers and Their
Opposites on a Number Line
The opposite of –7 is 7.
1 2 3 4 5 6 7
–7–6–5–4–3–2–1 0
7 units 7 units
9.
Course 2
2-1 Integers
Graphthe integer 5 and its opposite on a
number line.
Check It Out: Example 1
The opposite of –5 is 5.
1 2 3 4 5 6 7
–7–6–5–4–3–2–1 0
5 units 5 units
10.
Course 2
2-1 Integers
Youcan compare and order integers by
graphing them on a number line.
Integers increase in value as you move
to the right along a number line. They
decrease in value as you move to the
left.
11.
Course 2
2-1 Integers
Comparethe integers. Use < or >.
Additional Example 2A: Comparing Integers Using a
Number Line
4 is farther to the right than -4, so 4 > -4.
1 2 3 4 5 6 7
–7–6–5–4–3–2–1 0
4 -4
>
The symbol < means “is less than,” and the
symbol > means “is greater than.”
Remember!
12.
Course 2
2-1 Integers
Comparethe integers. Use < or >.
Additional Example 2B: Comparing Integers Using a
Number Line
-9 is farther to the right than -15, so -15 < -9.
-15 -9
>
-15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1
13.
Course 2
2-1 Integers
Comparethe integers. Use < or >.
Check It Out: Example 2A
6 is farther to the right than -6, so 6 > -6.
1 2 3 4 5 6 7
–7–6–5–4–3–2–1 0
6 -6
>
14.
Course 2
2-1 Integers
Comparethe integers. Use < or >.
Check It Out: Example 2B
-4 is farther to the right than -11, so -4 > -11.
-4 -11
>
-15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1
15.
Course 2
2-1 Integers
Usea number line to order the integers
from least to greatest.
Additional Example 3: Ordering Integers Using a
Number Line.
–3, 6, –5, 2, 0, –8
The numbers in order from least to greatest
are –8, –5, –3, 0, 2, and 6.
1 2 3 4 5 6 7 8
–8 –7–6 –5–4 –3 –2 –1 0
16.
Course 2
2-1 Integers
CheckIt Out: Example 3
Use a number line to order the integers from
least to greatest.
–5, 4, –3, 2, –1, –2
The numbers in order from least to greatest
are –5, –3, –2, –1, 2, and 4.
1 2 3 4 5 6 7 8
–8 –7–6–5–4 –3–2 –1 0
17.
Course 2
2-1 Integers
Anumber’s absolute value is its distance
from 0 on a number line. Since distance can
never be negative, absolute values are never
negative. They are always positive or zero.
18.
Course 2
2-1 Integers
Usea number line to find each absolute value.
Additional Example 4A: Finding Absolute Value
|8|
1 2 3 4 5 6 7 8
–8 –7–6–5–4 –3–2 –1 0
8 units
8 is 8 units from 0, so |8| = 8.
19.
Course 2
2-1 Integers
Thesymbol is read as “the absolute value of.”
For example -3 is the absolute value of -3.
Reading Math
20.
Course 2
2-1 Integers
AdditionalExample 4B: Finding Absolute Value
Use a number line to find each absolute value.
|–12|
–12 –11 –10 –9 –8 –7 –6 –5 –4 –3 –2 –1 0 1 2
–12 is 12 units from 0, so |–12| = 12.
12 units
21.
Course 2
2-1 Integers
Usea number line to find each absolute value.
|3|
1 2 3 4 5 6 7 8
–8 –7–6–5–4 –3–2 –1 0
3 units
3 is 3 units from 0, so |3| = 3.
Check It Out: Example 4A
22.
Course 2
2-1 Integers
Usea number line to find the absolute value.
|–9|
–9 is 9 units from 0, so |–9| = 9.
9 units
Check It Out: Example 4B
–12 –11 –10 –9 –8 –7 –6 –5 –4 –3 –2 –1 0 1 2
23.
Course 2
2-1 Integers
LessonQuiz: Part I
Compare. Use <, >, or =.
1. –32 32
2. 26 |–26|
3. –8 –12
4. Use a number line to order the integers –2, 3,
–4, 5, and –1 from least to greatest.
=
<
>
1 2 3 4 5
•
–5–4 –3 –2–1 0
•
• •
• –4, –2, –1, 3, 5
24.
Course 2
2-1 Integers
LessonQuiz: Part II
Use a number line to find the absolute value.
5. -3
3
1 2 3 4 5
–5 –4 –3 –2 –1 0
•
3 units
