This document provides definitions and examples related to basic algebra concepts. It defines key terms like variable, algebraic expression, and evaluating expressions. It discusses using letters to represent unknown numbers and combining like terms. It provides word phrases that relate to addition and subtraction and examples of writing algebraic expressions from word problems. The document also includes a section on evaluating expressions when a variable is given a number value and completing a table by performing algebraic operations.

1. Algebra I
Mr. Clutter
Villegas Middle School
Library
2006-2007

2. Definitions
• Variable – A variable is a letter
or symbol that represents a
number (unknown quantity).
• 8 + n = 12

3. Definitions
• A variable can use any letter of
the alphabet.
•n+5
•x–7
• w - 25

4. Definitions
• Algebraic expression – a group of
numbers, symbols, and variables
that express an operation or a
series of operations.
• m+8
• r–3

5. Definitions
• Evaluate an algebraic expression –
To find the value of an algebraic
expression by substituting numbers
for variables.
• m+8 m=2 2 + 8 = 10
• r–3 r=5 5–3=2

6. Definitions
• Simplify – Combine like terms
and complete all operations
m=2
•m+8+m 2m+8
• (2 x 2) + 8 4 + 8 = 12

7. Words That Lead to Addition
• Sum
• More than
• Increased
• Plus
• Altogether

8. Words That Lead to Subtraction
• Decreased
• Less
• Difference
• Minus
• How many more

9. Write Algebraic Expressions
for These Word Phrases
• Ten more than a number n + 10
• A number decrease by 5 w-5
• 6 less than a number x-6
• A number increased by 8 n+8
• The sum of a number & 9 n+9
• 4 more than a number y+4

10. Write Algebraic Expressions
for These Word Phrases
• A number s plus 2 s+2
• A number decrease by 1 k-1
• 31 less than a number x - 31
• A number b increased by 7 b+7
• The sum of a number & 6 n+6
• 9 more than a number z+9

11. Evaluate each algebraic
expression when x = 10
•x+8 18
• x + 49 59
•x+x 20
•x-x 0
•x-7 3
• 42 - x 32

12. Complete This Table
n n-3
5 2
10 7
21 18
32 29

13. Complete This Table
x x+6
5 11
10 16
21 27
32 38

14. Write an Algebraic Expression
for These Situations
• Scott’s brother is 2 years younger than
Scott
s-2
• The sum of two numbers is 12
v + c = 12
• The difference between two numbers is 5
m–n=5

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