21st Century Lessons
Equivalent Expressions
1
Warm Up
OBJECTIVE: Students will be able to identify when two expressions are equivalent.
Language Objective: Students will be able to explain in writing why two
expressions are equivalent.
Evaluate the following expressions.
when x = 2
1. 9x 6
2. 5(x  3) when x = 4
3. 2x  5y when x = 6, y = 4
Scaffold
2
24
35
32
Agenda
Agenda:
OBJECTIVE: Students will be able to identify when two expressions are equivalent.
Language Objective: Students will be able to explain in writing why two
expressions are equivalent.
1) Warm Up
Individual
4 minutes
2) Launch
A Disagreement- Whole Class
4 minutes
3) Explore
Which Mathematical Statement is True?Partners
20 minutes
4) Summary
Which Mathematical Statement is True?Whole Class
Matching- Partners
13 minutes
5) Practice
6) Assessment Exit Slip- Individual, Whole Class
5
15 minutes
4 minutes
Launch- A Disagreement
Harry and Louis are arguing whether the following
expressions are equal.
?
5 x  5x
What do you think? Provide evidence to support your
thinking.

Agenda
6
Explore- Which Mathematical Statement is True?
With your partner, decide which equations are true
for all values of x and y.
Part I. Give a written explanation to support your
answer.
Part II.
a. Pick any number for the variable(s)
b. Substitute the number into the equation to
prove if it is true.
c. Repeat this with a different number.
Example
7
Agenda
Summary- Which Mathematical Statement is True?
Click an equation.
2
?
xx x
Click to advance to the Practice Activity.
?
x  x  x  x  4x
?
2x 10 12x
?
3xy  3x  y
?

5x  2y  7xy
?
3(2x)  6x

Agenda
9
Practice- Matching
Directions: Decide which expressions on the left hand side
of the worksheet are equivalent to the expression on the
right hand side. Be sure to provide evidence by
substituting in ANY value for the variable, x, you choose.
5(4x) 
4(x 5) 
(34)x 
4(x  2) 
4(x 1)  3 
Agenda
16

Assessment- Exit Slip
Decide which equation is equal. Provide a
written explanation and proof by choosing a
value for x.
?
1. 5x 6 11x
5(2) 6 11(2)
106  22
16 22 
Not Equal
x 2
?
2. 3(x 2)  4  3x 10
3(22)  4  3(2) 10



17
3(4)  4  610
12 4 16
16 16
Equal
Agenda