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Flip Those Numbers!

Lesson Plan

Commutative Property Lesson Plan

Students will be able to identify and demonstrate the commutative property of addition, understanding that changing the order of addends does not change the sum.

Understanding the commutative property simplifies addition, builds confidence in number relationships, and provides a powerful tool for solving math problems more efficiently.

Audience

Kindergarten, 1st Grade

Time

15 minutes

Approach

Interactive discussion and hands-on activities.

Materials

Prep

Preparation Steps

5 minutes

  1. Review all generated materials: Commutative Property Lesson Plan, Slide Deck: Commutative Number Fun, Warm Up: Number Swaps, Worksheet: Order Up!, Discussion: Share Your Sums, and Quiz: Match the Math.
  2. Gather enough small counters or manipulatives for students to use during the warm-up and introduction (e.g., 5-10 per student).

Step 1

Warm-Up: Number Swaps

3 minutes

  1. Begin with the Warm Up: Number Swaps activity.
  2. Ask students to show two small groups of counters, like 2 red counters and 3 blue counters.
  3. Have them count the total. Then, ask them to switch the order of the groups (3 blue and 2 red) and count again. Did the total change?
  4. Repeat with another set of numbers (e.g., 1 and 4).

Step 2

Introduction: Does Order Matter?

4 minutes

  1. Use the Slide Deck: Commutative Number Fun to introduce the concept.
  2. Explain that in math, especially with addition, sometimes the order of the numbers doesn't change the answer.
  3. Show visual examples on the slide deck, reinforcing the 'flipping' idea with numbers and objects.

Step 3

Activity: Order Up! Worksheet

5 minutes

  1. Distribute the Worksheet: Order Up!.
  2. Guide students through the first one or two problems, demonstrating how to draw or write the two different orders for the same addition problem and then write the sum.
  3. Circulate and assist students as they complete the worksheet, encouraging them to use their counters if needed.

Step 4

Discussion: Share Your Sums

3 minutes

  1. Bring the class back together for the Discussion: Share Your Sums.
  2. Ask students to share their observations from the worksheet. 'What did you notice when you flipped the numbers?' 'Did your total change?'
  3. Emphasize that for addition, the order doesn't change the sum.

Step 5

Cool-Down/Assessment: Match the Math Quiz

Optional

  1. If time allows, use the Quiz: Match the Math as a quick cool-down or informal assessment to check for understanding.
  2. This can be done individually or as a class review.
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Slide Deck

Does Order Matter?

Today, we're going to see if changing the order of numbers changes our answer when we add them!

Welcome students and introduce the idea of playing with numbers. Ask if they think the order of things always matters.

Let's Try It!

Look at these blocks:

2 blue blocks + 3 red blocks = ?

Now, let's flip them:

3 red blocks + 2 blue blocks = ?

Show the first example. Use physical counters or point to the visuals on the slide. "Here we have 2 blue blocks and 3 red blocks. How many total?" Then, "What if we put the 3 red blocks first and then the 2 blue blocks? How many total now?"

More Fun With Numbers!

What about fruits?

1 apple + 4 bananas = ?

If we put the bananas first:

4 bananas + 1 apple = ?

Reinforce the concept with another example. "We have 1 apple and 4 bananas. Total? What if we start with the bananas?"

Your Turn to Predict!

If you know that 4 + 2 = 6...

What do you think 2 + 4 will be?

Will the answer be different? Why or why not?

Engage students with a predictive question. Have them think-pair-share or just call out answers. "If we know 4 + 2, what will 2 + 4 be?"

The Big Idea!

When you add numbers, you can switch their places, and the total (the sum) stays the same!

It's like a number flip-flop!

Summarize the commutative property in simple terms. "So, when we add, we can flip the numbers, and the total stays the same!"

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Warm Up

Warm Up: Number Swaps!

Objective: To visually and kinesthetically explore how changing the order of groups of objects doesn't change the total.

Instructions:

  1. Count and Show: Give each student or pair a small handful of counters (e.g., 5-6 total). Ask them to make two different groups with their counters. For example, ask them to show "2 red and 3 blue" counters.
  2. Count the Total: Have them count how many counters they have in total.
  3. Flip It! Now, ask them to switch the order of their groups. So, if they had "2 red and 3 blue," they now have "3 blue and 2 red." Did the total number of counters change?
  4. Discuss: Ask students to share what they noticed. Did the total stay the same even though the order changed?

This warm-up helps students physically manipulate objects to see that the overall quantity remains constant regardless of the arrangement, setting the stage for the commutative property.

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Worksheet

Order Up! Addition Fun

Name: _________________________

Directions: Look at the pictures or numbers. Write the addition problem two different ways, then write the total!

Problem 1:

Three apples and two bananas (Imagine 3 apples and 2 bananas drawn here)

____ + ____ = ____


____ + ____ = ____


Problem 2:

One sun and four clouds (Imagine 1 sun and 4 clouds drawn here)

____ + ____ = ____


____ + ____ = ____


Problem 3:

Numbers: 2 and 4

____ + ____ = ____


____ + ____ = ____


Problem 4:

Numbers: 1 and 3

____ + ____ = ____


____ + ____ = ____


Challenge Problem (Draw your own!):

Draw two different groups of objects. Write the addition problem two ways and find the total.

____ + ____ = ____


____ + ____ = ____










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Discussion

Share Your Sums: Does Order Matter?

Objective: To encourage students to verbalize their understanding of the commutative property of addition.

Instructions: Gather students for a brief discussion after completing the worksheet or warm-up.

Discussion Prompts:

  1. What did you notice about the addition problems on your worksheet or during our 'Number Swaps' warm-up?

    • Possible follow-up: Did you get the same answer every time you flipped the numbers around?



  2. Can someone show us one of their problems from the worksheet and explain what happened when they changed the order of the numbers?

    • Possible follow-up: Why do you think that happens?



  3. Imagine you have 2 cookies and then get 3 more. How many do you have? Now, what if you had 3 cookies first and then got 2 more? Is it still the same amount?

    • Possible follow-up: Can you think of other times in real life where the order doesn't change the total?



  4. So, what's our big discovery today about adding numbers? Does the order of the numbers change the final answer when we add?

    • Possible follow-up: What's a simple way you could tell a friend about this math idea?



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Quiz

Match the Math Quiz

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Flip Those Numbers! • Lenny Learning