Page 181 - Basic College Mathematics with Early Integers

Chapter 2 Vocabulary Check

Fill in each blank with one of the words or phrases listed below.

signed positive opposites negative absolute value variable integers
1. Two numbers that are the same distance from 0 on a number line but are on opposite sides of 0 are called
.
2. Together, positive numbers, negative numbers, and 0 are called numbers.
3. The of a number is that number’s distance from 0 on a number line.
4. The are Á , -3, -2, -1, 0, 1, 2, 3, Á .
5. A letter used to represent a number is called a(n) .
6. The numbers are numbers less than zero. Are you preparing for your test?
7. The numbers are numbers greater than zero. Don’t forget to take the Chapter 2Test on page 165.
Then check your answers at the back of the text and
use the Chapter Test Prep Videos to see the fully
2 Chapter Highlights worked-out solutions to any of the exercises you
want to review.

Definitions and Concepts Examples

Section 2.1 Introduction to Variables and Algebraic Expressions

A letter used to represent a number is called a variable. Variables:

x, y, z, a, b
A combination of operations on variables and numbers Algebraic expressions:
is called an algebraic expression. 3
3 + x, 7y, x + y - 10
Replacing a variable in an expression by a number, and Evaluate 2x + y for x = 22 and y = 4.
then finding the value of the expression, is called
#
2x + y = 2 22 + 4 Replace x with 22 and y with 4.
evaluating the expression for the variable.
= 44 + 4 Multiply.
= 48 Add.
Section 2.2 Introduction to Integers

Together, positive numbers, negative numbers, and 0 are -432, -10, 0, 15
called signed numbers.
The integers are Á , -3, -2, -1, 0, 1, 2, 3, Á .
The absolute value of a number is that number’s distance ƒ -2ƒ = 2 2 units
from 0 on a number line.The symbol for absolute value
is ƒ ƒ. 3 2 1 0 1 2 3
ƒ2ƒ = 2 2 units

3 2 1 0 1 2 3
Copyright 2012 Pearson Education, Inc. Copyright 2012 Pearson Education, Inc.
Two numbers that are the same distance from 0 on a 5 and -5 are opposites.
number line but are on opposite sides of 0 are called 5 units 5 units
opposites.
5 4 3 2 1 0 1 2 3 4 5

If a is a number, then -1-a2 = a. -1-112 = 11. Do not confuse with ––3=–3

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