Variable Lab Practice Worksheet
Math Lab 9 SPED Algebra Support
Evaluating Expressions
Name:
Date:
Period:
The 3-Step Substitution Blueprint
Rule: Always use parentheses ( ) when you plug in!
1 PARENT-UP
Replace the variable with parentheses ( ).
\( 3x + 4 \rightarrow 3(\quad) + 4 \)
2 DROP IT IN
Drop the given number inside the parentheses.
\( \text{If } x = 5 \rightarrow 3(5) + 4 \)
3 CALCULATE
Use order of operations (PEMDAS) to simplify.
\( 15 + 4 = 19 \)
Part 1: Guided Practice (One-Step Warm-Up)
Follow each guided frame
#1
Evaluate \( x + 9 \) for \( x = 6 \)
Step 1: Rewrite with ( )
Step 2: Plug in 6
Step 3: Add
Final Answer:
#2
Evaluate \( 20 - y \) for \( y = 7 \)
Step 1: Rewrite with ( )
Step 2: Plug in 7
Step 3: Subtract
Final Answer:
#3
Evaluate \( 5m \) for \( m = 8 \)
Step 1: Rewrite with ( )
Step 2: Plug in 8
Step 3: Multiply \( 5 \times 8 \)
Final Answer:
#4
Evaluate \( \frac{k}{4} \) for \( k = 24 \)
Step 1: Rewrite with ( )
Step 2: Plug in 24
Step 3: Divide \( 24 \div 4 \)
Final Answer:
Hint: A number right next to a variable like \( 5m \) means MULTIPLY! Page 1 of 3
Part 2
Two-Step Expressions
Name:
Order of Operations (PEMDAS):
1. Multiply / Divide 2. Add / Subtract
#5
\( 2x + 5 \) • for \( x = 7 \)
Show Work (Substitute & Solve):
Answer:
#6
\( 3a - 4 \) • for \( a = 6 \)
Show Work (Substitute & Solve):
Answer:
#7
\( 10 + 4y \) • for \( y = 3 \)
Show Work (Substitute & Solve):
Answer:
#8
\( 25 - 2p \) • for \( p = 8 \)
Show Work (Substitute & Solve):
Answer:
#9
\( \frac{m}{3} + 8 \) • for \( m = 15 \)
Show Work (Substitute & Solve):
Answer:
#10
\( 5(w - 2) \) • for \( w = 9 \)
Show Work (Substitute & Solve):
Answer:
Remember: For #10, do what is inside the parentheses first! Page 2 of 3
Part 3 & 4
Two Variables & Real-World Math
Name:
Level Up: Exponents & Two Variables
\( x^2 \) means \( x \times x \)
#11
\( x^2 + 6 \) • for \( x = 4 \)
Answer:
#12
\( 2y^2 \) • for \( y = 3 \)
Answer:
#13
\( a + 3b \) • for \( a = 5, b = 4 \)
Answer:
#14
\( 4m - 2n \) • for \( m = 6, n = 5 \)
Answer:
Part 4: Real-World Scenarios
Plug in the value to solve
#15 • Movie Pass
A theater pass costs \( 12 + 5t \) dollars, where \( t \) is the number of tickets bought.
Find the total cost if you buy \( t = 4 \) tickets:
Total Cost:
$
#16 • Lawn Mowing
Marcus charges \( 15h + 10 \) dollars to mow yards, where \( h \) is the number of hours worked.
How much does he earn if he works \( h = 5 \) hours?
Total Earned:
$
Self-Check: How confident do you feel evaluating expressions?
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Awesome work! Double-check your arithmetic and units ($). Page 3 of 3
