The Action of Subtraction

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Lesson Plan for Year 2nd Grade Students

Date: Thursday, November 28, 2024
Grade Level(s): 1/2
Subject/Strand: Math / Number Sense and Numeration

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Lesson Overview

Students will explore subtraction concepts such as "taking away" and "finding the difference." Using the interactive read-aloud The Action of Subtraction, students will uncover subtraction strategies through storytelling and hands-on activities.

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Educational Standards

Ontario Curriculum Overall Expectations

Grade 1:

• B1. Number Sense: Demonstrate an understanding of numbers and make connections to the way numbers are used in everyday life.

Grade 2:

• B1. Number Sense: Demonstrate an understanding of numbers and make connections to the way numbers are used in everyday life.

Ontario Curriculum Specific Expectations

Grade 1: B1.2

• Compose and decompose whole numbers up to and including 50, using a variety of tools and strategies, in various contexts.

Grade 2: B1.1

• Read, represent, compose, and decompose whole numbers up to and including 200, using a variety of tools and strategies, and describe various ways they are used in everyday life.

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Big Idea/Enduring Understanding

• Using different strategies to solve subtraction problems by finding the difference between two numbers.

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Essential/Key Questions

• How can we use different strategies to solve subtraction problems?
• How can we use "take away" to solve problems?

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Student Learning Goals

• We are learning to solve subtraction problems by using strategies and tools to take away and find the difference.

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Student Success Criteria

• I can understand what it means to take away and find the difference when solving subtraction problems.
• I can use different strategies and tools to solve subtraction problems.
• I can explain how I solved a subtraction problem.
• I can read a subtraction problem and identify what is being asked.

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Learning Skills and Work Habits

• Responsibility: Students use materials and tools effectively.
• Collaboration: Partner work encourages shared learning.
• Initiative: Students take an active role in finding subtraction strategies.
• Self-Regulation: Students manage their time to complete activities effectively.

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Pre-Knowledge and Vocabulary

Prior Knowledge

• Understanding subtraction as "take away".
• Familiarity with number lines and counters.

New Vocabulary

• Difference
• Take away
• Counting back
• Number line
• Minus
• Fewer
• Less
• Remaining

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Resources and Materials

• The Action of Subtraction (book)
• Visual subtraction anchor chart.
• Number lines (classroom set).
• Plastic counters (2 per student).
• Perma board (for whole-group modeling).
• Task cards with subtraction word problems.
• Whiteboards and markers (for each student).

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Assessment Methods for Learning

• Assessment FOR Learning: Observations of students during problem-solving and guided practice.
• Assessment AS Learning: Students reflect on the strategies they used and evaluate which worked best.
• Assessment OF Learning: Collection of work samples, anecdotal notes, and verbal explanations during wrap-up.

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3-Part Lesson Plan

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Minds On (5 minutes)

Objective: Establish connection to prior learning and activate schema.

• 1. Set the Context:
  Begin by holding up The Action of Subtraction.

  • “What do you already know about subtraction?”
  • Recall a prior lesson on sharing oranges using subtraction. Say, “Remember when Miss Chan and I shared oranges, and we had to figure out how many were left? That was subtraction!”

• 2. Activate Thinking:

  • “What strategies do we already know that can help us subtract?” (e.g., take away, number line, using tools).
  • Students take turns sharing what strategies they’ve used before.

Differentiation:

• For students needing additional support, allow verbal or gesture-only contributions. Reinforce visually using the key subtraction vocabulary on an anchor chart.

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Action (12 minutes)

Objective: Students build hands-on experiences with subtraction using storytelling and manipulatives.

Step-by-step Activity:
1. Read Aloud:

• Read The Action of Subtraction, pausing to ask scaffolded questions:
  • “If Sally had 10 cupcakes and ate 4, how can we find out how many are left?”
  • “Which tools could we use to help us?”

2. Demonstration:

• Use the Perma board and counters to model the subtraction problem in the story:
  • Demonstrate “taking away” 4 counters from 10.
  • Write the equation: 10 - 4 = 6.

3. Guided Partner Work:

• Provide students with subtraction task cards and manipulatives.
  • Each pair solves a task card using either counters, number lines, or their fingers.
  • Circulate and scaffold as needed (e.g., “What happens if we take 2 away from 8? How many are left?”).

4. Hands-On Independent Work:

• Students use whiteboards to independently solve subtraction problems (teacher-provided).
  • For example: “12 birds were sitting in a tree. 5 flew away. How many birds are left?”

Differentiation:

• Simplified numbers for some students (e.g., working with numbers 1–10 instead of larger ones).
• Verbal prompts for students who need support in reading task cards.

Assessment:

• Anecdotal notes on how students approach subtraction problems.
• Observation: Are students using tools effectively (e.g., counters, number lines)?

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Consolidation (4 minutes)

Objective: Reinforce and share learning.

• 1. Class Review:

  • Bring the class together. Ask, “What subtraction strategy worked best for you today?”
  • Highlight key student ideas and solutions on the board.

• 2. Mini Reflection Circle:

  • “What could we do if the problem gets harder, like subtracting from 15 or 20?”
  • Guide the connection between tools (like counters or number lines) for more challenging problems.

• 3. Wrap-Up Question:
  Ask, “If you had 20 jellybeans and someone ate 8, how could you solve it?” (Encourage sharing one strategy.)

Differentiation:

• Allow verbal responses or drawings for students who find it difficult to articulate solutions.

Assessment:

• Reflection on the strategies used during class discussion.
• Take notes on which strategies students mention and how confidently they share.

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Differentiation Summary

• Environment: Offer quiet spaces like the learning carpet for independent problem-solving.
• Content: Simplified tasks for students with lower numeracy levels, or added challenging problems for advanced learners.
• Process: Provide scaffolded one-on-one instruction as needed.
• Product: Accept drawn responses, verbal explanations, and equations.

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Estimated Total Lesson Time: 21 minutes