Page 37 - Algebra 1

L E5S S O N Finding Absolute Value and Adding Real Numbers
Warm Up
1. Vocabulary The set of ____________ (integers, real numbers) includes all
(1)
Simplify. 2.54.2-27.38
(SB 2)
4.1.09+76.9 (SB 2)
rational or irrational numbers.
New Concepts The absolute value of a number is the distance from the number to zero on a number line. The absolute value of 4 is written ⎪4⎥.
4
3._1 +_3 (SB 3) 2 8
5._3 -_3 (SB 3) 4 8
4
Simplify.
a. ⎪0⎥
SOLUTION
The absolute value of 0 is 0.
c. ⎪1-_3⎥ 4
SOLUTION
First simplify within the absolute-value bars. Then find the absolute value.
1-_3 = _1 =_1 ⎪ 4⎥⎪4⎥4
b. ⎪7.12⎥
SOLUTION
-4 -3 -2 -1 0 1 2 3 4 opposites
⎪-4⎥ = 4
Finding the Absolute Value
⎪4⎥ = 4
Absolute Value
The absolute value of a number n is the distance from n to 0 on a number line.
Example
1
The distance from 7.12 to 0 is 7.12. So the absolute value is 7.12.
d. -⎪11-2⎥ SOLUTION
First simplify within the absolute-value bars. Then find the absolute value.
-⎪11-2⎥=-⎪9⎥=-9
Reading Math
Read -⎪9⎥ as the opposite of the absolute value of 9.
22 Saxon Algebra 1