Unit 3

Find the Difference

Lesson 5

Adding and Subtracting Within 20

Expressions and Equations

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Let’s find differences within 10.

Unit 3 ● Lesson 5

Learning

Goal

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Missing Value Within 10

Unit 3 ● Lesson 5 ● Warm-up

Find the number that makes each equation true.

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Number Talk

Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.

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Different Ways to Find the Difference

Unit 3 ● Lesson 5 ● Activity 1

Mai, Diego, and Noah find the value of 10 – 6.

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1. Diego says, “I can take away.”

What does Diego mean?

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• Mai says, “I can count on.”

What does Mai mean?

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• Noah says, “I can use what I know about 6 + 4 to help me.”

What does Noah mean?

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Be ready to explain your thinking in a way that others will understand.

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Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.

Different Ways to Find the Difference

Unit 3 ● Lesson 5 ● Activity 1

• Who can restate what _____ just showed us?
• Which method do you like best?

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Activity Synthesis

Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.

Subtraction Number Strings

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Unit 3 ● Lesson 5 ● Activity 2

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Find the value of each difference in the subtraction string.

Explain what you notice.

Set 1:

6 – 1

6 – 2

6 – 3

6 – 4

What do you notice?

Why do you think this happens?

Be ready to explain your thinking in a way that others will understand.

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Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.

Subtraction Number Strings

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Unit 3 ● Lesson 5 ● Activity 2

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Set 2:

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9 – 8

9 – 7

9 – 6

9 – 5

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What do you notice?

Why do you think this happens?

Be ready to explain your thinking in a way that others will understand

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Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.

Subtraction Number Strings

Unit 3 ● Lesson 5 ● Activity 2

Just like addition, there are patterns in subtraction. Understanding patterns can help you find difference.

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Activity Synthesis

Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.

The Value of the Difference

Unit 3 ● Lesson 5 ● Activity 3

Find the value of each difference.

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1. 9 – 6
2. 10 – 3
3. 7 – 3
4. 9 – 5
5. 8 – 6
6. 6 – 5
7. 9 – 4
8. 10 – 7

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Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.

The Value of the Difference

Unit 3 ● Lesson 5 ● Activity 3

Were there any expressions that helped you with another expression? How did they help you?

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Activity Synthesis

Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.

Find the Difference

Unit 3 ● Lesson 5

• Today we found differences within 10 and saw that you can use what you know about addition to find differences. To find the difference in a problem like you can think about the sums of 9. I know that 5 + 4 = 9 , so 9 – 5 = 4 .
• We say that 4, 5, and 9 are related. We can write both addition and subtraction equations with these numbers.
• What are the addition and subtraction equations we can write with 4, 5, and 9?

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Lesson Synthesis

Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.

Subtraction within 10

Unit 3 ● Lesson 5

Find the value of the differences.

Show your thinking using drawings, numbers, or words.

1. 9 – 6
2. 10 – 3

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Cool-down

Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.

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Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.