Multiplication and Division, Part 1

Lesson 4

Objective

Identify and create situations involving an unknown number of groups and find the number of groups in situations.

Materials and Resources

Common Core Standards

Core Standards

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  • 3.OA.A.1 — Interpret products of whole numbers, e.g., interpret 5 × 7 as the total number of objects in 5 groups of 7 objects each. For example, describe a context in which a total number of objects can be expressed as 5 × 7.

  • 3.OA.A.2 — Interpret whole-number quotients of whole numbers, e.g., interpret 56 ÷ 8 as the number of objects in each share when 56 objects are partitioned equally into 8 shares, or as a number of shares when 56 objects are partitioned into equal shares of 8 objects each. For example, describe a context in which a number of shares or a number of groups can be expressed as 56 ÷ 8.

  • 3.OA.A.3 — Use multiplication and division within 100 to solve word problems in situations involving equal groups, arrays, and measurement quantities, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.

Criteria for Success

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  1. Represent the number of groups and size of groups in a picture.
  2. Divide a number of objects into groups of a given size in order to find the number of groups. 
  3. Write a multiplication equation to represent a given situation or picture where the unknown is the number of groups, including the number of rows of an array (MP.2). 
  4. Draw a picture to represent a given multiplication equation where the unknown is the number of groups, including the number of rows of an array (MP.2).

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Anchor Tasks

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Problem 1

Split 18 counters equally into groups of two. 

a. How many counters do you have in each group? 

b. Write a multiplication equation to represent this situation. 

How is this similar to Anchor Task #1 from Lesson 4? How is it different?

Guiding Questions

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Problem 2

a. Ms. Holcombe picked the apples below this weekend. She wants to put 2 apples in a bag to give to each of her friends. 

i. Write a multiplication equation to represent this problem. 

ii. How many bags of apples did Ms. Holcombe fill? 

b. A grocery store puts 15 watermelons on display. They arrange them in rows of 5. 

i. Write a multiplication equation to represent this problem. 

ii. How many rows of watermelon are there?

Guiding Questions

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Problem 3

Draw a picture or write a story to represent this multiplication situation. Then find the solution. 

___ $$\times 4 = 12$$

Guiding Questions

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References

EngageNY Mathematics Grade 3 Mathematics > Module 1 > Topic B > Lesson 5Concept Development

Grade 3 Mathematics > Module 1 > Topic B > Lesson 5 of the New York State Common Core Mathematics Curriculum from EngageNY and Great Minds. © 2015 Great Minds. Licensed by EngageNY of the New York State Education Department under the CC BY-NC-SA 3.0 US license. Accessed Dec. 2, 2016, 5:15 p.m..

Modified by The Match Foundation, Inc.

Discussion of Problem Set

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  • What was similar about #8 and #9? What was different? 
  • How did your visual models in #11 and #12 help you to determine the unknown factor? Did anyone use a different strategy to solve?
  • Did you “just know” the missing factor for any of the problems? Which one(s)?
  • How is your approach to drawing a model to represent a problem with an unknown number of groups different from your approach to drawing a model to represent a problem with an unknown group size? 
  • How are the multiplication sentences we wrote today different from those we wrote yesterday? What explains this difference? 

Target Task

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Problem 1

Split 12 triangles into groups of 6 to find the number of groups. 

____ $$\times 6 = 12$$

References

EngageNY Mathematics Grade 3 Mathematics > Module 1 > Topic B > Lesson 5Exit Ticket, Question #1

Grade 3 Mathematics > Module 1 > Topic B > Lesson 5 of the New York State Common Core Mathematics Curriculum from EngageNY and Great Minds. © 2015 Great Minds. Licensed by EngageNY of the New York State Education Department under the CC BY-NC-SA 3.0 US license. Accessed Dec. 2, 2016, 5:15 p.m..

Modified by The Match Foundation, Inc.

Problem 2

Spencer buys 20 strawberries to make smoothies. Each smoothie needs 5 strawberries. How many smoothies can Spencer make? Show or explain your work.

References

EngageNY Mathematics Grade 3 Mathematics > Module 1 > Topic B > Lesson 5Exit Ticket, Question #2

Grade 3 Mathematics > Module 1 > Topic B > Lesson 5 of the New York State Common Core Mathematics Curriculum from EngageNY and Great Minds. © 2015 Great Minds. Licensed by EngageNY of the New York State Education Department under the CC BY-NC-SA 3.0 US license. Accessed Dec. 2, 2016, 5:15 p.m..

Modified by The Match Foundation, Inc.

Mastery Response

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