Writing Algebraic Expressions

Writing Algebraic
Expressions
Objective:
Be able to write an algebraic
expression for a word phrase or write a
word phrase for an expression.


Warm Up
Evaluate each algebraic expression for the
given value of the variables.

46

1.)

7x + 4 for x = 6

2.)

8y – 22 for y = 9

3.)

12x 8
y+

4.)

y + 3z for y = 5 and z = 6

50

for x = 7 and y = 4

86
23


Although they are closely
related, a Great Dane weighs
about 40 times as much as a
Chihuahua.

An expression for the weight of the
Great Dane could be 40c, where c is the
weight of the Chihuahua.

When solving real-world problems, you will need
to translate words, or verbal expressions, into
algebraic expressions.


Notes
In order to translate a word
phrase into an algebraic
expression, we must first
know some key word
phrases for the basic
operations.

On the back of your notes:
Addition

Subtraction

Multiplication

Division


Addition Phrases:
More than
Increase by
Greater than
Add
Total
Plus
Sum


Subtraction Phrases:
Decreased by
Difference between
Take Away
Less
Subtract
Less than*
Subtract from*

Multiplication Phrases:
Product
Times
Multiply
Of
Twice or double
Triple


Division Phrases:
Quotient
Divide
Divided by
Split equally


Notes
Multiplication expressions should
be written in side-by-side form,
with the number always in front of
the variable.
3a
2t
1.5c
0.4f


Notes
• Division expressions should be

written using the fraction bar
instead of the traditional
division sign.
 c
t

2

5

3
x


Examples
Addition phrases:

3 more than x


the sum of 10 and a number c



a number n increased by 4.5


Examples
Subtraction phrases:
 a number t decreased by 4





the difference between 10 and a
number y
6 less than a number z


Examples
Multiplication phrases:

the product of 3 and a number t


twice the number x



4.2 times a number e


Examples
Division phrases:


the quotient of 25 and a number b



the number y divided by 2



2.5 divide g


Examples
converting f feet into inches
a car travels at 75 mph for h hours
the area of a rectangle with a length
of 10 and a width of w


Examples
converting i inches into feet

the cost for tickets if you purchase 5 adult
tickets at x dollars each
the cost for tickets if you purchase 3
children’s tickets at y dollars each


Examples
the total cost for 5 adult tickets and 3
children’s tickets using the dollar
amounts from the previous two
problems (problems e and f)