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Number Ninjas Unite!

Lesson Plan

Number Ninjas Unite!

Students will fluently add and subtract within 20, using numbers from 1-10 and 1-20.

Mastering basic addition and subtraction facts is foundational for all future math learning. Strong computation skills build confidence and are crucial for tackling more complex math problems.

Audience

2nd Grade

Time

15 minutes

Approach

Through guided instruction, interactive slides, and focused practice problems.

Materials

Small whiteboards or scratch paper, Markers or pencils, Number Ninjas Slide Deck, Number Ninjas Worksheet, and Number Ninjas Answer Key

Prep

Prepare Materials

5 minutes

Step 1

Warm-Up & Introduction (2 minutes)

2 minutes

Step 2

Guided Practice: Numbers 1-10 (5 minutes)

5 minutes

  • Move to the 'Numbers 1-10 Challenge' slide of the Number Ninjas Slide Deck.
    - Guide students through a few example problems involving addition and subtraction within 10. Encourage them to use strategies like counting on, counting back, or using mental math.
    - Ask students to share their strategies.

Step 3

Guided Practice: Numbers 1-20 (5 minutes)

5 minutes

  • Transition to the 'Numbers 1-20 Challenge' slide of the Number Ninjas Slide Deck.
    - Present problems involving addition and subtraction within 20. Emphasize making tens or breaking apart numbers.
    - Work through a few problems together, asking students to explain their thinking.

Step 4

Independent Practice & Wrap-Up (3 minutes)

3 minutes

  • Distribute the Number Ninjas Worksheet.
    - Instruct students to complete the worksheet independently.
    - Circulate to provide individual support and feedback.
    - Collect worksheets. Briefly review one or two problems as a group or have students check their answers using the Number Ninjas Answer Key if time allows. Reiterate the importance of practice.
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Slide Deck

Number Ninjas Unite!

Master Your Math Facts within 20!

Greet students warmly. Ask them what they think a "Number Ninja" does. Emphasize that mastering math facts makes them powerful problem-solvers.

Our Mission Today:

Sharpen your addition skills!
Boost your subtraction power!
Become a math master with numbers up to 20!

Explain the objective clearly. "Today, we're going to practice adding and subtracting numbers up to 20. Why is this important? Because being quick and accurate with these numbers helps us with ALL math!"

Challenge 1: Numbers 1-10

Let's warm up our brains with sums and differences within 10!

Examples:
5 + 3 = ?
9 - 4 = ?
7 + 2 = ?
8 - 6 = ?

Introduce the first challenge. "Let's start with smaller numbers, up to 10. Think about strategies you already know: counting on, counting back, using your fingers, or even drawing pictures."

Challenge 2: Numbers 1-20

Ready to level up?

Examples:
12 + 5 = ?
18 - 6 = ?
7 + 9 = ?
15 - 8 = ?

Transition to the next challenge. "Great job with numbers up to 10! Now, let's level up our ninja training to numbers up to 20. Remember, you can use strategies like making a ten or breaking apart numbers."

Your Mission, Should You Choose To Accept It...

Time for independent practice!

Complete the Number Ninjas Worksheet.
Show what you know!

Explain that it's time for independent practice. "You've done an amazing job practicing together! Now it's your turn to show off your ninja skills on the worksheet. Work quietly and do your best!"

Mission Accomplished!

You're on your way to becoming a Math Master!

Keep practicing your addition and subtraction facts!

Conclude the lesson. "Fantastic work today, Number Ninjas! Keep practicing your math facts every day, and you'll become unstoppable!"

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Worksheet

Number Ninjas Worksheet

Name: ________________________
Date: ________________________

Part 1: Numbers 1-10 Challenge!

Solve these problems. Show your work or explain your thinking.

  1. 5 + 4 =


  2. 9 - 3 =


  3. 2 + 7 =


  4. 8 - 5 =


  5. 6 + 3 =


Part 2: Numbers 1-20 Challenge!

Solve these problems. Use any strategy you know!

  1. 10 + 7 =


  2. 15 - 4 =


  3. 9 + 8 =


  4. 17 - 5 =


  5. 6 + 13 =


  6. 19 - 7 =


  7. 11 + 9 =


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Answer Key

Number Ninjas Answer Key

Part 1: Numbers 1-10 Challenge!

  1. 5 + 4 = 9

    • Thought Process: Start at 5 and count on 4: 6, 7, 8, 9.

  2. 9 - 3 = 6

    • Thought Process: Start at 9 and count back 3: 8, 7, 6.

  3. 2 + 7 = 9

    • Thought Process: It's often easier to start with the larger number. Start at 7 and count on 2: 8, 9.

  4. 8 - 5 = 3

    • Thought Process: Think: What number plus 5 equals 8? 3 + 5 = 8. So, 8 - 5 = 3.

  5. 6 + 3 = 9

    • Thought Process: Start at 6 and count on 3: 7, 8, 9.

Part 2: Numbers 1-20 Challenge!

  1. 10 + 7 = 17

    • Thought Process: Adding to a group of ten is like replacing the zero with the number you are adding. 10 + 7 makes 17.

  2. 15 - 4 = 11

    • Thought Process: Subtract the ones place: 5 - 4 = 1. The ten remains the same, so it's 11.

  3. 9 + 8 = 17

    • Thought Process: You can make a ten! Take 1 from the 8 and add it to the 9 to make 10. Now you have 10 + 7 = 17.

  4. 17 - 5 = 12

    • Thought Process: Subtract the ones place: 7 - 5 = 2. The ten remains the same, so it's 12.

  5. 6 + 13 = 19

    • Thought Process: Combine the ones: 6 + 3 = 9. Keep the ten from 13. So, 10 + 9 = 19.

  6. 19 - 7 = 12

    • Thought Process: Subtract the ones place: 9 - 7 = 2. The ten remains the same, so it's 12.

  7. 11 + 9 = 20

    • Thought Process: You can make a ten! Take 1 from the 11 and add it to the 9 to make 10. Now you have 10 (remaining from 11) + 10 (from 9+1) = 20.
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