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Multiply More Decimals

Grade 5: Unit 5: Lesson 21

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Lesson Purpose

The purpose of this lesson is for students to use place value understanding and multi-digit whole number products to find multi-digit decimal products.

Lesson Narrative

In this lesson, students use place value understanding and properties of operations to find products of decimals. The numbers are more complex in this lesson so diagrams representing the products are less helpful. Students find the values of both types of expressions they have worked with in the last several lessons, products of two decimals to the tenth and products of a whole number and a decimal to the hundredth. Students find the products using a strategy of their choice. When they explain their reasoning, students will apply their understanding of place value to relate decimal products to whole number products based on the repeated reasoning they have acquired (MP3, MP7, MP8).

Learning Goals

•Calculate products of decimals using whole number products and place value understanding.

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Let’s multiply decimals.

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Estimation Exploration:

Central Park

Warm-Up

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Central Park is a large park in Manhattan. It is about 3.85 kilometers long and 0.79 km wide.

What is the area of Central Park?

Record an estimate that is:

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Multiply More Decimals

Activity 1

MLR2: Collect and Display

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Choose Your Strategy

Activity 2

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Lesson Synthesis

Today we found products of whole numbers and decimals.

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Lesson Synthesis

How is finding products of whole numbers and decimals the same as finding products of whole numbers? How is it different?

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Explain Why Expressions are Equal

Cool-Down

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Cool-Down

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Image Citations

https://pixabay.com/photos/gemstone-amethyst-602252/

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