Balance Scale Lesson Plan
Grade 1 • Unit 3 Day 3 45-Minute Inquiry Plan
Balancing Sums & Differences
CCSS 1.OA.D.7
Equivalence & The Equal Sign
Lesson Objective
SWBAT evaluate if addition and subtraction equations are true or false, and rewrite false equations to make them equal (totals ≤ 20).
Key Vocabulary
Equal (=): Same value
Equivalent: Equal amounts
Equation: Balanced sentence
Materials
Unifix cubes (2 colors), whiteboards & markers, balance scale anchor chart.
45-Min Pacing: Warm-Up (8m) • Launch (10m) • Practice & Monitor (12m) • Discourse (10m) • Stamp & Exit (5m)
Part 1
Math Meeting & Fast Facts Sprint
8 Minutes
1. Oral Counting (3 min):
- Choral count to 60 by 1s, 2s, 5s, and 10s forwards and backwards.
- Pointer tracks on 100s chart; cold-call transition numbers.
2. Fast Facts (+0, +1) Routine (5 min):
- 60s flashcard practice (cold-call automatic recall).
- 60s independent sprint quiz → peer/choral answer verification.
Part 2
Inquiry Launch: The Scale Must Balance
10 Minutes
Prior Knowledge Anchor (2 min):
Prompt: "What does the equal sign actually tell us?" → Key Takeaway: It is not a signal to calculate; it is a balance beam showing that the left quantity has the exact same value as the right quantity.
Hook Challenge on Board: 9 − 4 = 3 + 6
Step 1: Test the Balance (3 min)
Scholars solve both sides on whiteboards:
Left: 9 − 4 = 5 | Right: 3 + 6 = 9
× Unbalanced (5 ≠ 9) → False Equation!
Step 2: Balance the Equation (5 min)
Turn & Talk: "How can we change one side so the scale balances?"
• Change Right: Make it equal 5 → 9 − 4 = 3 + 2
• Change Left: Make it equal 9 → 9 − 0 = 3 + 6
Teacher Bright Line & Transition:
"Mathematicians, today you have 12 minutes to evaluate whether equations are true or false. If an equation is false, your job is to rewrite it so both sides balance perfectly!"
1st Grade Math Inquiry • Balancing Sums & Differences Page 1 of 2 • Launch & Lesson Core
Monitoring & Discourse Protocols
Facilitation & Responsive Teaching
27 Minutes Remaining
Part 3
Academic Monitoring & Error Correction
12 Minutes
Error 1: Assumes equation is true if left side total is near right side Value Confusion
Teacher Prompt: "Build the left side with blue cubes. Build the right side with red cubes. Put them side-by-side. Are they the exact same height? If they are not equal, the sentence is false."
Error 2: Looks at the number after '=' as just "the answer" (e.g., 8 − 4 = 4 + 2) Operational '=' Misconception
Teacher Prompt: "I see 8 − 4 = 4. But look at the whole right side! What is 4 + 2? Does 4 equal 6? No! Both sides must balance completely."
Error 3: Rewrites equation but new expressions are still unequal Check Strategy
Teacher Prompt: "What is your target value for the left side? Now evaluate your new right side. What does it equal? Did your scale balance or tip?"
Part 4
Chart for Sophistication & Discourse
10 Minutes
Mathematician 1: Concrete Model
Student counts all or uses cube towers to verify each side:
5 − 4 = 1 • 3 + 6 = 9 • 1 ≠ 9
Mathematician 2: Mental / Known Fact
Student counts on or uses known addition/subtraction facts:
"I know 3+6 is 9, and 5-4 is 1. Not equal!"
Key Comparison Prompts:
• "Both mathematicians discovered the equation was false. How did they prove it?"
• "Scholar A changed the left side, and Scholar B changed the right side. Are both solutions correct? Why?" (Both created equations where Left = Right!)
Part 5
Stamp & Exit Ticket Assessment
5 Minutes
Core Takeaway Stamp:
“When two expressions are equal, both sides have the exact same value. An equation is balanced when the left amount equals the right amount.”
Differentiation Pathways:
Support: Provide Visual Support worksheet with ten-frames and sentence stem: "This is false because ___ does not equal ___."
Extension: Rewrite equations using both an addition AND subtraction expression.
1st Grade Math Inquiry • Balancing Sums & Differences Page 2 of 2 • Facilitation & Assessment
Equal Scales Workspace Practice
Name:
Date:
Unit 3 • Lesson 3
Equal Scales: True or False?
Directions 1. Solve each side in the box. 2. Circle True or False.
Problem 1
True False
5 − 4 = 3 + 6
Show Left Side Work: Show Right Side Work:
Problem 2
True False
9 + 2 = 13 − 1
Show Left Side Work: Show Right Side Work:
Problem 3
True False
4 + 3 = 10 − 3
Show Left Side Work: Show Right Side Work:
Problem 4
True False
9 + 7 = 16 − 2
Show Left Side Work: Show Right Side Work:
1st Grade Math • Balancing Sums and Differences Page 1 of 2
Name:
Date:
Challenge Practice
Balancing Larger Numbers
Solve both sides in the workspaces. Circle True or False.
Problem 5
True False
6 + 5 = 13 − 2
Left Work: Right Work:
Problem 6
True False
10 − 4 = 4 + 10
Left Work: Right Work:
Problem 7
True False
14 + 4 = 20 − 2
Left Work: Right Work:
Problem 8
True False
18 − 5 = 7 + 7
Left Work: Right Work:
Problem 9 Grand Champion Challenge
True False
15 + 4 = 11 + 8
Show Left Side Work (15 + 4): Show Right Side Work (11 + 8):
1st Grade Math • Balancing Sums and Differences Page 2 of 2
Equal Scales Visual Practice
Name:
Date:
Visual Math Studio • Grade 1
Equal Scales: Visual Balancers
Directions 1. Count the dots on each side. 2. Write the values. 3. Circle True or False.
Problem 1
True False
5 − 4 = 3 + 6
Left: 5 − 4
×
×
×
×
Left Total:
Right: 3 + 6
Right Total:
Does the left total equal the right total?
Problem 2
True False
9 + 2 = 13 − 1
Left: 9 + 2
+ 1 more:
Left Total:
Right: 13 − 1
and 3 more: ×
Right Total:
Does the left total equal the right total?
Problem 3
True False
4 + 3 = 10 − 3
Left: 4 + 3
Left Total:
Right: 10 − 3
×
×
×
Right Total:
Does the left total equal the right total?
Problem 4
True False
9 + 7 = 16 − 2
Left: 9 + 7
+ 6 more: 10 + 6 = 16
Left Total:
Right: 16 − 2
+ 6 dots, cross off 2: × ×
Right Total:
Does the left total equal the right total?
1st Grade Math • Visual Support Balancers Page 1 of 2
Name:
Date:
Visual Math Studio • Part 2
Scale Champions: Visual Balancers
Solve Both Sides • Circle True or False
Problem 5
True False
6 + 5 = 13 − 2
6 + 5
Left Total:
13 − 2
× ×
Right Total:
Does 11 balance with 11?
Problem 6
True False
10 − 4 = 4 + 10
10 − 4
× × × ×
Left Total:
4 + 10
Right Total:
Does 6 balance with 14?
Problem 7
True False
8 + 3 = 14 − 3
8 + 3
Left Total:
14 − 3
× × ×
Right Total:
Does 11 balance with 11?
Problem 8
