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Subtract & Conquer!

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Lesson Plan

Subtract & Conquer!

Students will subtract numbers within 10 accurately using various strategies (e.g., counting back, using a number line, mental math) to solve problems.

Understanding subtraction within 10 is a fundamental math skill that helps students solve everyday problems like sharing toys or calculating how many cookies are left. It builds confidence and a strong foundation for future math concepts.

Audience

2nd Grade Students

Time

30 minutes

Approach

Interactive slides, guided practice, and independent application.

Materials

Smartboard or Projector, Warm-Up: Subtract & Solve!, Slide Deck: Subtract & Conquer!, Worksheet: Subtraction Challenge, Answer Key: Subtraction Challenge, and Pencils

Prep

Teacher Preparation

10 minutes

Step 1

Introduction & Warm-Up

5 minutes

  • Engage: Greet students and introduce the day's math adventure:

Step 2

Mini-Lesson: Subtraction Strategies

10 minutes

  • Direct Instruction: Use the Slide Deck: Subtract & Conquer! to teach and review subtraction strategies.
    • Slide 2: What is Subtraction? Explain subtraction as taking away or finding the difference. Give simple examples.
    • Slide 3: Counting Back Demonstrate counting back on fingers or a number line. Example: 8 - 3.
    • Slide 4: Using a Number Line Show how to use a number line to jump backward. Example: 9 - 4.
    • Slide 5: Mental Math/Fact Families Briefly introduce how knowing addition facts can help with subtraction. Example: If 3 + 4 = 7, then 7 - 3 = 4.
  • Guided Practice: Work through a few examples together as a class, encouraging students to use different strategies.

Step 3

Independent Practice: Worksheet Challenge

10 minutes

  • Activity: Distribute the Worksheet: Subtraction Challenge.
  • Instructions: Explain that students will complete the worksheet independently, applying the strategies learned.
  • Support: Circulate around the classroom to provide individual support and answer questions. Observe student strategies.
  • Differentiation: For students needing more support, work with a small group using manipulatives. For early finishers, challenge them to create their own subtraction problems within 10.
  • Collect: Collect worksheets upon completion.

Step 4

Wrap-Up & Review

5 minutes

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Slide Deck

Subtract & Conquer!

Your Mission: Master Subtraction Within 10!

Get ready to become a subtraction superhero!

Greet students warmly. Ask them what they know about subtraction. Introduce the idea of becoming 'Subtraction Superheroes' today!

What is Subtraction?

It's all about taking away!

  • When you subtract, you take away a number from another.
  • It tells you how many are left.
  • It can also tell you the difference between two numbers.

Example: 7 - 3 = ?

Explain subtraction simply: taking away or finding the difference. Use concrete examples if possible, like 5 apples and taking 2 away. Emphasize keywords like 'take away,' 'minus,' 'how many left,' 'difference.'

Strategy 1: Counting Back

Take a step back!

  • Start with the bigger number.
  • Count backward the number you are subtracting.

Example: 8 - 3
Start at 8. Count back 3: 7, 6, 5.
So, 8 - 3 = 5!

Demonstrate with fingers or by pretending to count back. Start with the larger number and count backward the smaller number of times. Do a quick example with the class.

Strategy 2: Using a Number Line

Jump, jump, jump backward!

  • Find the first number on the number line.
  • Jump backward (to the left) the number you are subtracting.
  • Where you land is your answer!

Example: 9 - 4 = ?
(Number line image from 0-10)

Draw a quick number line on the board or use a projected one. Show how to start at the first number and jump backward. Emphasize that each jump is one count.

Bonus Strategy: Fact Families!

Addition helps with subtraction!

  • If you know your addition facts, you already know many subtraction facts!

Example: If 3 + 4 = 7, then...

  • 7 - 3 = 4
  • 7 - 4 = 3

They're a family!

Explain how knowing addition facts helps. If you know 3+4=7, then you automatically know 7-3=4 and 7-4=3. This is a powerful mental math trick.

Time to Practice!

Your Turn!

Now it's time to show what you know. You'll get a worksheet to practice subtraction within 10.

Remember to use the strategies we just learned!

Have students work on the worksheet independently. Remind them to use any strategy they like. Circulate to provide support.

You are Subtraction Superheroes!

Great job today!

Keep practicing your subtraction skills!

  • Which strategy did you like the most?
  • What's one new thing you learned about subtraction?

Conclude the lesson by reinforcing confidence and the importance of practice. Thank them for being great learners.

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Warm Up

Subtract & Solve!

Directions: Solve the following subtraction problems. Show your work or strategy if you can!

  1. 7 - 2 =


  2. 10 - 4 =


  3. 6 - 3 =


  4. 9 - 1 =


  5. 5 - 5 =


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Worksheet

Subtraction Challenge!

Directions: Read each problem carefully and solve it using any strategy you like (counting back, number line, fact families). Show your answer!

  1. 8 - 5 =





  2. 9 - 3 =





  3. 10 - 7 =





  4. 6 - 2 =





  5. 7 - 0 =





  6. 4 - 4 =





  7. If you have 5 cookies and eat 2, how many cookies are left?





  8. There are 9 birds on a branch. 3 fly away. How many birds are still on the branch?





  9. You have 10 crayons. Your friend borrows 4. How many crayons do you have now?





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Answer Key

Subtraction Challenge Answer Key

Warm-Up: Subtract & Solve!

  1. 7 - 2 = 5
    • Thought Process: Start at 7 and count back 2: 7... 6, 5. Or, I know 5 + 2 = 7.
  2. 10 - 4 = 6
    • Thought Process: Start at 10 and count back 4: 10... 9, 8, 7, 6. Or, I know 6 + 4 = 10.
  3. 6 - 3 = 3
    • Thought Process: Start at 6 and count back 3: 6... 5, 4, 3. Or, I know 3 + 3 = 6.
  4. 9 - 1 = 8
    • Thought Process: Start at 9 and count back 1: 9... 8. Or, I know 8 + 1 = 9.
  5. 5 - 5 = 0
    • Thought Process: When you take away all of something, you have 0 left.

Worksheet: Subtraction Challenge

  1. 8 - 5 = 3
    • Thought Process: Start at 8, count back 5: 8... 7, 6, 5, 4, 3.
  2. 9 - 3 = 6
    • Thought Process: Start at 9, count back 3: 9... 8, 7, 6.
  3. 10 - 7 = 3
    • Thought Process: Think: 7 + ? = 10. The missing number is 3.
  4. 6 - 2 = 4
    • Thought Process: Use a number line: Start at 6, jump back 2. You land on 4.
  5. 7 - 0 = 7
    • Thought Process: Taking away zero means you still have the same amount.
  6. 4 - 4 = 0
    • Thought Process: If you have 4 and take away 4, you have none left.
  7. Answer: 3 cookies are left.
    • Thought Process: 5 - 2 = 3.
  8. Answer: 6 birds are still on the branch.
    • Thought Process: 9 - 3 = 6.
  9. Answer: You have 6 crayons now.
    • Thought Process: 10 - 4 = 6.
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Cool Down

Subtraction Reflection

Directions: Answer the questions below about our subtraction lesson today.

  1. What is one new thing you learned about subtraction or one strategy you found helpful?





  2. Give an example of when you might use subtraction in your everyday life.





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lenny

Lesson Plan

Minus Mission: Within 10

Students will be able to accurately subtract numbers within 10 by using various strategies, demonstrating their understanding through guided practice and independent activities.

Mastering subtraction within 10 is a foundational skill that helps students build strong number sense, develop problem-solving abilities, and prepare for more complex mathematical operations.

Audience

2nd Grade Students

Time

30 minutes

Approach

This lesson uses engaging slides, interactive discussions, and hands-on practice to solidify understanding.

Materials

Our Subtraction Adventure Slide Deck, Warm-Up: Ready to Subtract!, Subtraction Story Script, Subtraction Challenge Worksheet, and Cool-Down: Show What You Know!

Prep

Teacher Preparation

10 minutes

Step 1

Warm-Up: Number Line Dash

5 minutes

  1. Begin with the Warm-Up: Ready to Subtract! activity to activate prior knowledge of number order.
    2. Discuss student responses, briefly reviewing the concept of 'taking away' or 'finding the difference'.

Step 2

Introduction: What is Subtraction?

5 minutes

  1. Present the first few slides of the Our Subtraction Adventure Slide Deck.
    2. Use the Subtraction Story Script to introduce subtraction as 'taking away' or 'finding the difference'.
    3. Engage students with examples using visual aids or manipulatives.

Step 3

Guided Practice: Subtraction Strategies

10 minutes

  1. Continue through the Our Subtraction Adventure Slide Deck, introducing strategies like counting back, using a number line, and fact families.
    2. Facilitate interactive examples, encouraging students to share their strategies.
    3. Provide opportunities for students to work through problems as a class or in pairs.

Step 4

Independent Practice: Subtraction Challenge

7 minutes

  1. Distribute the Subtraction Challenge Worksheet.
    2. Instruct students to complete the worksheet independently, applying the strategies learned.
    3. Circulate the room to offer support and answer questions.

Step 5

Cool-Down: Quick Check

3 minutes

  1. Conclude the lesson with the Cool-Down: Show What You Know! activity.
    2. Collect the cool-down responses to assess student understanding and inform future instruction.
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Slide Deck

Minus Mission: Within 10

Get ready to become subtraction superheroes!

Welcome students and introduce the exciting "Minus Mission" ahead. Briefly recap what subtraction means in simple terms.

What is Subtraction?

Subtraction means to take away or to find the difference between two numbers.

Example: If you have 5 apples and eat 2, how many are left?

Define subtraction with simple language. Emphasize 'taking away' or 'finding the difference.' Use a real-life example or have students suggest one.

Strategy 1: Counting Back

We can count back from the larger number to find the answer!

Example: 7 - 3 = ?

  • Start at 7.
  • Count back 3 numbers: 6, 5, 4.
  • So, 7 - 3 = 4!

Introduce the idea of using a number line to count back. Demonstrate a few examples. Emphasize starting at the first number and hopping back.

Strategy 2: Use Your Fingers!

You can use your fingers to help you subtract!

Example: 8 - 2 = ?

  • Hold up 8 fingers.
  • Put down 2 fingers.
  • How many are left? 6!

Introduce using fingers or drawing pictures. Demonstrate with an example, encouraging students to try it with their fingers.

Let's Practice!

Solve these problems together:

  • 10 - 4 = ?
  • 6 - 1 = ?
  • 9 - 5 = ?

Provide a few practice problems for students to solve together using either strategy. Encourage them to explain their thinking. Guide them through the Subtraction Challenge Worksheet once they're ready for independent practice.

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Warm Up

Warm-Up: Ready to Subtract!

Instructions: Look at the numbers below. Draw a line to match each number to its place on the number line. Then, write the number that comes right before it.

  1. Number: 5
    Before:


  2. Number: 8
    Before:


  3. Number: 3
    Before:


  4. Number: 10
    Before:





    ```
    0--1--2--3--4--5--6--7--8--9--10

**Think about it:** What does it mean to find the number that comes *before*? How is that like taking away?
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