Title: Example 4
Author: Kathy Halverson
Last saved by: MHE
Company: Halverson Household

Lesson 2-1

Example 1	Write Integers for Real-World Situations
Write an integer for each situation.
a.  a temperature decrease of 15°		The integer is –15.
b.  a gain of $310				The integer is +310.
c.  42 feet above sea level			The integer is +42.

Example 2	Compare Two Integers
Use the integers graphed on the number line below.

a.  Write two inequalities involving –3 and 1.
Since –3 is to the left of 1, write –3 < 1.
Since 1 is to the right of –3, write 1 > -3.

b.  Replace the      with < or > in –1     -4 to make a true sentence.

-1 is greater than –4 since it lies to the right of –4.  So write –1 > -4.

Example 3	Order Integers
FOOTBALL    During a football game, the Busytown Bees completed plays with the following results.  Yardage gains are expressed as positive integers and yardage losses are expressed as negative integers.  The results were –3, +12, +7, -10, -6, +24, +18, -12, -1, and +5.  Order the yardages from least to greatest.

Graph each integer on a number line.

Write the numbers as they appear from left to right.
The yardages –12, -10, -6, -3, -1, +5, +7, +12, +18, +24 are in order from least to greatest.

Example 4	Expressions with Absolute Value
Evaluate each expression.

6 units 

a.  ⏐-6⏐

⏐-6⏐ = 6		The graph of –6 is 6 units from 0.

b.  ⏐-3⏐ + ⏐9⏐		The absolute value of –3 is 3.
⏐-3⏐ + ⏐9⏐ = 3 + 9	The absolute value of 9 is 9.
		  = 12		Simplify.

Example 5	Algebraic Expressions with Absolute Value
ALGEBRA	Evaluate ⏐x⏐+ 4 if x = -9.

⏐x⏐ + 4 = ⏐-9⏐ + 4		Replace x with –9.
	  = 9 + 4		The absolute value of –9 is 9.
	  = 13			Simplify.