Expression Match Teacher Guide Teacher Facilitation Guide
Expression Experts Lab
Grade 7 Math: Algebra
Lesson Overview
Students will master the art of substituting integer values into algebraic expressions. The lesson emphasizes the correct order of operations (PEMDAS), specifically focusing on the common pitfall of multiplying before applying exponents.
Objective
Evaluate algebraic expressions by substituting specific values for variables using integers.
Materials Needed
Expression Match Slides
Expression & Answer Cards (pre-cut)
Tape or putty (to hide cards)
Exit Tickets
Pacing & Instructions
5 MIN
Warm-up: Substitution Relay
Organize students into groups. Project the relay problem on the board (Slide 2). One student from each group comes to the board at a time to solve a step of a multi-part expression.
Example: If x = 3, what is 2x + 5? (Answer: 11)
10 MIN
Instructional Video
Watch the "How To Evaluate Algebraic Expressions" video (0:00-4:29). Use the pause points to check for understanding.
2:50: Ask: "Why did he square the 2 before multiplying by 2 in the second example?"Discuss the importance of parentheses when substituting negative numbers.
20 MIN
Main Activity: Expression Match
Hand out "Expression Cards" to students. "Answer Cards" should be hidden around the room before class.
Students must evaluate their expression on paper, then find the physical card that matches their answer. Once found, they check in with the teacher for verification.
5 MIN
Reflection: Exit Ticket
Students independently solve the expression: \(2x^2 - y\) for \(x=3\) and \(y=5\). This tests both substitution and the order of operations discussed during the video pause.
Answer Key: Expression Match
1: 7
2: 21
3: 26
4: 20
5: -6
6: -9
7: 11
8: 6
9: 18
10: 4
Exit Ticket Answer: 13
Expression Match Slides Expression Experts
Substitution & Order of Operations
Substitution Relay
Evaluate the expression if x = 3 and y = -2:
\(4x + 2y - 1\)
Step 1: Substitute values
Step 2: Multiply
Step 3: Combine terms
Watch & Learn
Embedded media
Viewing focus: 0:00 - 4:29 (Examples 1-3)
Think Like a Pro
In Example 3, why did he square the 2 before multiplying by 2?
Common Error
\(2(2)^2 \rightarrow (4)^2 \rightarrow 16\)
Correct Path
\(2(4) \rightarrow 8\)
The Golden Rules
P Parentheses
E Exponents
M Multiplication
D Division
A Addition
S Subtraction
Pro Tip: Substitution
Always write substituted values in parentheses to keep track of negative numbers and multiplication!
Expression Match
01
Receive an Expression Card.
02
Evaluate it on your paper (show all steps!).
03
Find the matching Answer Card hidden in the room.
04
Check in with the Lab Director (Teacher) to verify.
Go hunt for those answers!
Exit Ticket
Independently evaluate the expression:
\(2x^2 - y\)
if x = 3 and y = 5
Hand your paper to the teacher before leaving.
Expression Match Cards Expression Match: Card Set
Instructional Resource
This document contains two sets of cards:
Expression Cards (Page 2): Hand these out to students. Each card contains a unique algebraic expression and variable values.
Answer Cards (Page 3): Hide these around the room before class. Each card contains a large number matching one of the expression solutions.
Teacher Tip:
Print the Answer Cards on colorful cardstock to make them easier for students to spot, or print on white and hide them in "tricky" places like the back of the door, under desks, or near the pencil sharpener!
Student Expression Cards (Cut along dotted lines)
#01
\(x + 12\)
if \(x = -5\)
#02
\(4y - 3\)
if \(y = 6\)
#03
\(a^2 + 1\)
if \(a = 5\)
#04
\(2(b + 3)\)
if \(b = 7\)
#05
\(c^2 - 10\)
if \(c = -2\)
#06
\(15 - 3x\)
if \(x = 8\)
#07
\(x^2 + 2y\)
if \(x=3, y=1\)
#08
\(10 / x + 4\)
if \(x=5\)
#09
\(2x^2\)
if \(x=3\)
#10
\(y - x^2\)
if \(y=20, x=4\)
Hidden Answer Cards (Hide these around the room)
7
21
26
20
-6
-9
11
6
18
4
Expression Evaluation Exit Ticket Exit Ticket
LAB-EX-001
Name:
Date:
Evaluate the following expression. Show all work.
\(2x^2 - y\)
if \(x = 3\) and \(y = 5\)
Show Your Work:
Final Answer:
Exit Ticket
LAB-EX-001
Name:
Date:
Evaluate the following expression. Show all work.
\(2x^2 - y\)
if \(x = 3\) and \(y = 5\)
Show Your Work:
Final Answer:
Exit Ticket
LAB-EX-001
Name:
Date:
Evaluate the following expression. Show all work.
\(2x^2 - y\)
if \(x = 3\) and \(y = 5\)
Show Your Work:
Final Answer:
Exit Ticket
LAB-EX-001
Name:
Date:
Evaluate the following expression. Show all work.
\(2x^2 - y\)
if \(x = 3\) and \(y = 5\)
Show Your Work:
Final Answer:
