1. 2
Chapter
Chapter 2
Integers and Introduction to Variables

2. Introduction to Variables and Algebraic Expressions
Section
2.1
Introduction to Variables and Algebraic Expressions

3. Evaluate Algebraic Expressions Given Replacement Values.
Objective A
Evaluate Algebraic Expressions Given Replacement Values.

4. Algebraic Expressions
A variable is a letter used to represent any number.
A constant is either a fixed number or a letter that represents a fixed number.
An algebraic expression is formed by numbers and variables connected by the operation of addition, subtraction, multiplication, division, raising to powers, and/or taking roots.

5. Terms
Definitions
Variable: A letter to represent all the numbers fitting a pattern.
Algebraic Expression: A combination of numbers, letters (variables), and operation symbols.
Evaluating the Expression: Replacing a variable in an expression by a number and then finding the value of the expression.
Objective A Continued

6. Evaluating Expressions
Example
Evaluating Expressions
Evaluate 7 + 3z when z = –3
Objective B

7. Evaluating Expressions
Example
Evaluating Expressions
Evaluate 2(x – y) for x = 8 and y = 4
Objective B

8. Translate Phrases into Variable Expressions.
Objective B
Translate Phrases into Variable Expressions.

9. Translating Phrases sum plus added to more than increased by total
Addition
(+)
Subtraction
(–)
Multiplication
(·)
Division
()
sum
plus
added to
more than
increased by
total
difference
minus
subtract
less than
decreased by
less
product
times
multiply
multiplied by of
double/triple
quotient
divide
shared equally among
per
divided by
divided into
Objective A

10. Example
Write as an algebraic expression. Use x to represent “a number.”
a.) 5 decreased by a number
b.) The quotient of a number and 12
a.) 5
decreased by
a number – 5 x
Objective A
The quotient of
b.)
a number
and 12 x  12