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Products Beyond 100

Grade 4: Unit 6: Lesson 5

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Lesson Purpose

The purpose of this lesson is for students to find the product of a one-digit number and a two-digit

number in ways that make sense to them.

Lesson Narrative

In grade 3, students learned about multiplication and learned to find products within 100. Earlier in

this course, students identified factors and multiples, performed multiplicative comparison with

whole numbers and fractions, and used the structure of base-ten numbers and properties of

operations to find multiples of 10, 100, 1,000, and so on.

This lesson is the first in a series focused on finding whole-number products beyond 100. Here,

students reason about equal-group situations involving one-digit and two-digit numbers in any way

that makes sense to them. In the first activity, students work with an array of objects to build on a

familiar representation. In the second activity, no visual representation is provided. Students may

find products by creating arrays or diagrams, decomposing a factor into smaller numbers or place

value, and using their understanding of properties of operations.

Learning Goals

• Multiply two-digit by one-digit whole numbers in ways that make sense to them.

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Let’s find products beyond 100.

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Number Talk: A Number Times Some Multiple of

10

Warm-Up

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` Find the value of each expression mentally.

8 x 30
5 x 30
10 x 30
15 X 30

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Let’s Talk About It!

How did the first three expressions help you find the value of 15 x 30 ?

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Elena’s Sticky Gift

Activity 1

MLR2: Collect and Display
MLR7: Compare and Connect

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Elena receives a sheet of fancy stickers as a gift.

How many stickers are there?

Explain or show how you would find out without counting every sticker.

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Let’s Talk About It!

Which ideas did you see the most as you walked around today?

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More and More Stickers

Activity 2

In this activity, students use strategies and representations that make sense to them to find

products beyond 100. As before, the context of stickers lends itself to be represented with an array.

The factors are large enough, however, that doing so would be inconvenient, motivating other

representations or strategies (MP2). Look for the ways that students extend or generalize previously

learned ideas or representations to find multiples of larger two-digit numbers. While many of the

student responses are written with expressions, students are not expected to represent their

reasoning using equations and expressions as this time. Teachers may choose to represent student

reasoning using equations and expression so students can start connecting representations.

After students work on the first problem, pause to discuss some possible representations for finding

the number of stickers. Each of the representations show different ways to represent the

decomposition of a factor and students may decompose the factors in a variety of ways.

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Make an estimate: Do you think Elena has fewer than 100 stickers, between 100 and 200, or more than 200?

a. Elena has another sheet of stickers that has 9 rows and 21 stickers in each row. How many stickers does Elena have? Explain or show your reasoning.

b. Noah’s sticker sheet has 3 rows with 48 stickers in each row. Andre’s sticker sheet has 7 rows with 23 stickers in each row.Who has more stickers? Explain or show your reasoning.

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Lesson Synthesis

3 x 48 = and 7 x 23 =

How would you find the value of each product?

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Rows of Seats

Cool-Down

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A theater has 8 rows of seats and 27 seats in each row. How many seats are in the theater? Show your reasoning.

Cool-Down: Rows of Seats

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Image Citations

https://giphy.com/gifs/perfect-galaxy-infinity-n9sSVtgf78Qqk

https://giphy.com/gifs/refinery29-isabelcastillo-l4hLGvgARVqVFLlIc

https://unsplash.com/photos/2vGtWsOTySE

https://giphy.com/gifs/office-crew-rowing-iRzlyqHL8hJTy

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