21st Century Lessons
Writing Algebraic Expressions
1
Warm Up-Matching
OBJECTIVE: SWBAT write an algebraic expression from a written
expression.
LANGUAGE OBJECTIVE: SWBAT discuss the difference between algebraic and written
expressions.
Choose the numerical expression that best matches each
written expression.
Numerical Expression
Written Expression
1) 3  9
a) the product of 9 and 3
2) 9  3
b) 9 subtracted by 3
3) 9  3
c) 9 divided by 3
4) 9  3
d) the sum of 3 and 9
Agenda
2
Agenda:
OBJECTIVE: SWBAT write an algebraic expression from a written
expression.
LANGUAGE OBJECTIVE: SWBAT discuss the difference between algebraic and written
expressions.
1) Warm Up Matching-Independent
2) Launch Operations to Words-Groups
3) Explore
4) Practice
Mini Lesson-Whole Class
Matching Expression-Whole Class and Partners
5) Assessment
Exit Slip-Independent and Partners
Agenda
3
Launch-Operations to Words
Directions: Put each word from the list into the operation’s box
that it most likely expresses.
Addition
Subtraction
Multiplication
Division
PC Users
4
plus
difference
less than
factors
decreased by
times
ratio
increased by
separate
minus
of
sum
product
multiplied
less
more than
in all
divided
quotient
per
subtract
each
twice
Agenda
Launch- Mac User
Directions: Put each word from the list into the operation’s box
that it most likely expresses.
Addition
Subtraction
Multiplication
Division
more than
plus
sum increased by
in all
difference
minus
less than decreased by
subtract
less
product factors
twice
of
each multiplied
times
divided
per
quotient
separate
ratio
Next Slide
5
plus
difference
less than
factors
decreased by
times
ratio
increased by
separate
minus
of
sum
product
multiplied
less
more than
in all
divided
quotient
per
subtract
each
twice
Agenda
Explore-Mini Lesson
Write the following as a numerical expression.
•The product of ten and seven.
10  7 or 10  7
•The product of ten and five.
10  5 or 10  5
•The product of ten and a number.
VARIABLE
Think…what can we use to represent a number when
we don’t know the number?
Click to reveal next part
Agenda
7
Explore- Mini Lesson
Variable: a letter or symbol that represents an
unknown quantity.
Write as a algebraic expression.
The product of ten and a
10  n 10  n
Now, for my next trick, I
introduce a new way
number. will
to write multiplication.
10n
A number written next to a
variable means multiplication.
Agenda
9
Explore- Mini Lesson
This new expression, 10n, is called an Algebraic Expression.
Why do mathematicians call them Algebraic Expressions?
• Algebraic Expression: an expression containing at least
one variable.
x
4n
5t  8
• Numerical Expression: an expression containing one or
more numbers and operations.
47
57  8
Click to reveal next part
Agenda
10
Explore- Mini Lesson
• Written Expression: an expression written with words.
The sum seventeen and number
Three times the difference of nine and seven
• Variable: any letter in the alphabet or symbol that
represents an unknown quantity.
n
p
h
Agenda
11
Practice- Whole Class
Write an algebraic expression for the problems
Important!!!!
below.
Identify the
a) The sum of ten and a number.
operation(s) by
10  x
underlining key
words.
b) The quotient of a number and twelve.
t  12
t
12
c) Eleven decreased by five times a number.
11  5n
Agenda
12
Practice- Partners
Name ________________
Date ___________
Class Work: Written Expressions vs. Algebraic Expressions
Directions: Match the written expressions in Column A with the
algebraic expressions in Column B.
COLUMN A
The sum of a
number and ten
The quotient of
a number and
eight
The product of
ten and a
number
increased by
eight
x  10
x  10
8x
10  x
10  3 x
10  2 x
Ten decreased
by three times
a number
10 x  8
8 x
Eight increased
by a number
2x  8
x
8
Eight less than
twice a number
Ten divided by
a number
The product of
eight and a
number
COLUMN B
Agenda
13
Practice- Summary
Class Work: Written Expressions vs. Algebraic Expressions
Directions: Match the written expressions in Column A with the algebraic expressions
in Column B.
COLUMN A
The sum of a
number and ten
The quotient of a
number and eight
The product of
ten and a number
increased by
eight
COLUMN B
x  10
x  10
8x
10  x
Ten divided by a
number
Eight less than
twice a number
10  3 x
10  2 x
The product of
eight and a
number
Ten decreased
by three times
a number
10 x  8
8 x
A number
decreased by ten
Eight increased
by a number
Ten more than
twice a number
2x  8
x
8
Agenda
14
Assessment- Exit Slip
Directions:
1) Write your own algebraic expression using n, 3, 5.
You must use at least 2 operations.
2) Translate your algebraic expression into a
written expression.
3) Turn and Talk: Read your written expression to
your partner. Have your partner write the algebraic
expression. Switch roles.
Agenda
15