Multiplication and Division, Part 1

Lesson 8

Objective

Build fluency with division facts using units of 2, 5, and 10.

Common Core Standards

Core Standards

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  • 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.B.6 — Understand division as an unknown-factor problem. For example, find 32 ÷ 8 by finding the number that makes 32 when multiplied by 8.

  • 3.OA.C.7 — Fluently multiply and divide within 100, using strategies such as the relationship between multiplication and division (e.g., knowing that 8 × 5 = 40, one knows 40 ÷ 5 = 8) or properties of operations. By the end of Grade 3, know from memory all products of two one-digit numbers.

Criteria for Success

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  1. Solve division and unknown factor problems involving twos, fives, and tens by skip-counting, keeping track on their papers or on their fingers of how many twos, fives, or tens have been counted, stopping the skip-counting sequence when they reach the dividend, knowing that the number of twos, fives, or tens that they counted is the solution. 

Tips for Teachers

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  • “For $$8\times3$$, you know the number of 3s and count by 3 until you reach 8 of them. For $$24\div 3$$, you count by 3 until you hear 24, then look at your tracking method to see how many 3s you have. Because listening for 24 is easier than monitoring the tracking method for 8 3s to stop at 8, dividing can be easier than multiplying” when using a skip-counting strategy to solve (OA Progression, p. 25). Thus, this lesson should be more accessible to students than Lesson 7.
  • As a supplement to the Problem Set, students can play the first version of "What's your Number?" from the Preferred Tasks in 3.OA.4 - About the Math, Learning Targets, and Rigor by the Howard County Public School System.

Remote Learning Guidance

If you need to adapt or shorten this lesson for remote learning, we suggest prioritizing Anchor Task 2 (benefits from worked example). Find more guidance on adapting our math curriculum for remote learning here.

Fishtank Plus

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  • Problem Set
  • Student Handout Editor
  • Google Classrom Integration
  • Vocabulary Package

 

Anchor Tasks

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Problem 1

Maureen says the skip-counting sequence “10, 20, 30, 40, 50, 60” to help her solve a problem.

a. What multiplication problem might Maureen be trying to solve? How do you know? 

b. What if Maureen was solving a division problem? What problem might that have been? 

Guiding Questions

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Problem 2

Solve. 

a.   $$12\div2 =$$ _____

b.   _____ $$=35\div 5$$

c.   $$90\div 10=$$  _____

d.   _____ $$\times 5 = 45$$

e.   $$2 \times$$ _____ $$=16$$

Guiding Questions

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Problem Set & Homework

Discussion of Problem Set

  • I think the answer in #3f is 8. Do you agree or disagree? What mistake did I make? 
  • What do you notice about #11a and #11d? What do you wonder? 
  • Is division commutative? How do you know? 

Target Task

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Solve.

1.   $$90 \div 10 =$$ _____                                    2.   ____ $$\times 2 = 8$$                                     3.   $$40 = 5\times $$ _____

Mastery Response

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Additional Practice

Unit Practice

With Fishtank Plus you can access our Daily Word Problem Practice and our content-aligned Fluency Activities created to help students strengthen their application and fluency skills.

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