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Unit 2

Fractional Side Lengths Less Than 1

Lesson 10

Fractions as Quotients and Fraction Multiplication

Expressions and Equations

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Let’s find the area of rectangles with a fractional side length.

Unit 2 ● Lesson 10

Learning

Goal

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What is the Area?

Unit 2 ● Lesson 10 ● Warm-up

What is the area of the shaded region?

Record an estimate that is:

  • Is more than half or less than half of the rectangle shaded?
  • How can you use this to help make your estimate?
  • Based on this discussion does anyone want to revise their estimate?

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Estimation Exploration

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

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Rectangle With a Fractional Side Length

Unit 2 ● Lesson 10 ● Activity 1

If the height of the shaded region was of a square unit, what expression could you write to represent the area of the shaded region?

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Launch

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

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Rectangle With a Fractional Side Length

Unit 2 ● Lesson 10 ● Activity 1

Write a multiplication expression to represent the area of each shaded region. Then find the area.

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

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Rectangle With a Fractional Side Length

Unit 2 ● Lesson 10 ● Activity 1

  • How does this expression relate to the second and third shaded regions?
  • Why are the areas of these two shaded regions different?

  • How are the second and third shaded regions the same? How are they different?

  • The expressions for the area show that there are 12 shaded pieces in both but they are different sizes.

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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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What Are the Side Lengths?

Unit 2 ● Lesson 10 ● Activity 2

  1. Write a multiplication expression to represent the area of the shaded region. What is the area?

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

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What Are the Side Lengths?

Unit 2 ● Lesson 10 ● Activity 2

  • Here are two diagrams. Consider each expression and decide whether it represents the shaded region in one of the diagrams. Be prepared to share your thinking.

  1. For each diagram, what is the area?

X

Y

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

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What Are the Side Lengths?

Unit 2 ● Lesson 10 ● Activity 2

  • How did you determine the side lengths for shaded region in diagram X?

  • How does this expression represent the shaded region in diagram X?

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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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Fractional Side Lengths Less Than 1

Unit 2 ● Lesson 10

  • Today we found the area of rectangles with a whole number side length and a fractional side length.
  • What are some different expressions that represent the shaded region?
  • Pick one of the expressions and explain to your partner how it represents the shaded region.

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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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A Fractional Side Length

Unit 2 ● Lesson 10

  1. Write a multiplication expression to represent the area of the shaded region.

  • Find the area of the shaded region.

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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.