Lesson 11

Workshop: Multiply and Divide Fractions

Est. Class Sessions: 1–2

Summarizing the Lesson

Conclude the Workshop by discussing Check-In: Questions 15–16.

Ask:

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  • What is the problem in Question 15 asking you to find out? (How much of the pan of brownies is each piece if she cuts 1/3 of the pan into 3 equal pieces?)
  • Who would like to show how they represented 1/3 ÷ 3? (See Figure 4 for possible representations and solutions.)
  • Who can show a different representation?
  • How did you solve the problem? (See Figure 4.)
  • How did you label your answer? ( 1/9 pan)
  • How did you know to divide? (Possible response: The problem said she was cutting 1/3 of a pan into 3 smaller pieces so I knew to divide 1/3 by 3 and I knew the pieces would be smaller than 1/3 and smaller than 3.)
  • How is 1/3 ÷ 3 different from 3 ÷ 1/3 ? ( 1/3 ÷ 3 means you divide 1/3 evenly into 3 parts, and 3 ÷ 1/3 means you find how many thirds are in 3.)
  • What is the problem in Question 16 asking you to find out? (How much of the whole bag of flour did Mrs. Murphy use if she used 3/4 of 4/5 of it?)
  • How did you solve 3/4 × 4/5 ? (See Figure 5 for possible solution strategies.)
  • Did anyone solve the problem a different way? Show us.
  • How did you label your answer? ( 3/5 of a bag)
  • How do you know your answer is in simplest form? (Possible response: 3/5 is in simplest form because it uses the fewest fraction circle pieces, just 3 green pieces.)
  • Is 12/20 written in simplest form? How do you know? ( 12/20 is not in simplest form. Possible response: I can divide both the 12 and the 20 by 4 and reduce the fraction to 3/5.)
  • How did you know to multiply? (Possible response: The clue was in the way the question was worded. I knew 3/4 of 4/5 meant 3/4 × 4/5 .)
  • Is there a strategy on the Multiplying Fractions Menu or the Dividing Fractions Menu that you have a question about?
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Use Check-In: Questions 15–16 on the Find Fraction Products and Quotients pages in the Student Activity Book to assess students' abilities to represent multiplication and division of fractions with area models, number lines, number sentences, drawings, and stories [E3]; multiply and divide fractions using area models, drawings, and number lines [E4]; and represent an answer in simplest form [E2].

Student Guide:
Student Activity Book: 436
Answers
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SAB_Mini
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Master:
Many ways to represent and solve 1/3 ÷ 3
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Possible solution strategies for 3/4 × 4/5
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