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Unit 5

Add 2 Two-digit Numbers

Lesson 9

Adding Within 100

Expressions and Equations

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Let’s add two-digit numbers.

Unit 5 ● Lesson 9

Learning

Goal

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Make a Ten

Unit 5 ● Lesson 9 ● Warm-up

Find the value of each expression mentally.

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  • 38 + 2
  • 40 + 3
  • 38 + 5
  • 38 + 15

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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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How Did You Find the Value?

Unit 5 ● Lesson 9 ● Activity 1

Find the value of 17 + 36.

Show your thinking using drawings, numbers, or words.

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

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How Did You Find the Value?

Unit 5 ● Lesson 9 ● Activity 1

Let’s share how you found the value of 17 + 36.

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Activity Synthesis

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

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Grab and Add

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Unit 5 ● Lesson 9 ● Activity 2

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Round 1:

  • Grab a handful of towers of ten and a handful of single cubes.
  • I have ______________ cubes and my partner has ______________ cubes.
  • How many cubes do you and your partner have altogether?
  • Show your thinking using drawings, numbers, or words.

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Round 2:

  • I have ______________ cubes and my partner has ______________ cubes.
  • How many cubes do you and your partner have altogether?
  • Show your thinking using drawings, numbers, or words.

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

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Grab and Add

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Unit 5 ● Lesson 9 ● Activity 2

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Round 3:

  • I have ______________ cubes and my partner has ______________ cubes.
  • How many cubes do you and your partner have altogether?
  • Show your thinking using drawings, numbers, or words.

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Round 4:

  • I have ______________ cubes and my partner has ______________ cubes.
  • How many cubes do you and your partner have altogether?
  • Show your thinking using drawings, numbers, or words.

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

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Grab and Add

Unit 5 ● Lesson 9 ● Activity 2

How does the drawing show how they found the sum?

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Activity Synthesis

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

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Add 2 Two-digit Numbers

Unit 5 ● Lesson 9

Today we saw different ways we can add two-digit numbers. What new method did you try today, or are you excited to try tomorrow?

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Lesson Synthesis

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

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Find the Value

Unit 5 ● Lesson 9

Find the value of 18 + 55.

Show your thinking using drawings, numbers, or words.

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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.