Algebraic Expressions

Review

Variable – is a letter or symbol that represents an unknown quantity. X y Z n t

Algebraic expression- contains at least one variable and does not contain an equal signEX: T + 3

Since an algebraic expression contains a variable, we can evaluate the expression if we are given what the variable equals.

If m = 8, solve the expression m + 5.

m + 5

8 + 5

13

You can use algebraic expressions to explain a relationship between quantities.

Ex:Ex: Her math grade decreased by 6 points. Let g

represent the math grade.

g - 6

Words That Lead to Addition

• Sum

• More than

• Increased

• Plus

• Altogether

Words That Lead to Subtraction

• Decreased

• Less

• Difference

• Minus

• How many more

Words That Lead to Multiplication

• Product

• Total

• Area

• Times

• Of

Words That Lead to Division

• Share

• Distribute

• Quotient

• Average

Practice Problems

1. Five plus y

2. 6 times q

3. 2 less than x

ANSWERS

1. 5 + y

2. 6q

3. x - 2

Practice Problems

4. Evaluate 7y when y =2.

5. Evaluate 6 – w when w = 1.

ANSWERS

4. 14

5. 5

Write Algebraic Expressionsfor These Word Phrases

• Ten more than a number

• A number decrease by 5

• 6 less than a number

• A number increased by 8

• The sum of a number & 9

• 4 more than a number

n + 10

w - 5

x - 6

n + 8n + 9

y + 4

Write Algebraic Expressionsfor These Word Phrases

• A number s plus 2

• A number decrease by 1

• 31 less than a number

• A number b increased by 7

• The sum of a number & 6

• 9 more than a number

s + 2

k - 1

x - 31

b + 7n + 6

z + 9

Write an Algebraic Expression for These Situations

• Scott’s brother is 2 years younger than Scott

• The sum of two numbers is 12

• The difference between two numbers is 5

s - 2

v + c = 12

m – n = 5

Practice Problems6. A cake will serve 12

people. Write an expression for how many people will C cakes serve?

ANSWERS

6. 12c

Practice Problems7.The drama club sold 60

more tickets on Saturday as on Friday (f). Write an expression for the number of tickets sold on Saturday.

ANSWERS

7. f + 60