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Math lesson plan · 5th grade (Year 6 in England) · 45 minutes

Predict the size of a product: multiplying as scaling

Fractions

CCSS 5.NF.B.5.ACCSS 5.NF.B.5.BEngland: Y6 Fractions

Objective and success criteria

Students will: Predict the size of a product: multiplying as scaling.

  • I can answer questions on today's skill on my own, without help.
  • I can explain each step and say why it works.
  • I can check my answer and spot a mistake.

Before and after

Needs first: Multiply fractions

Leads to: the next skill in this area.

Materials: Fraction strips or a fraction wall, Paper strips to fold, Number lines, Mini whiteboards and pens, Printed student sheet (below).

Warm-up · 5 min

  • Quick retrieval from earlier learning (Multiply fractions). Students answer on mini whiteboards.
  • Show answers together and note who needs support in the main task.
  1. Diego has 16 metres of ribbon and uses 1/4 of it. How many metres is that? → 4Prompt: "Of" means multiply: 1/4 × 16.
  2. Diego has 40 metres of ribbon and uses 1/5 of it. How many metres is that? → 8Prompt: "Of" means multiply: 1/5 × 40.
  3. Noah has 40 metres of ribbon and uses 3/8 of it. How many metres is that? → 15Prompt: "Of" means multiply: 3/8 × 40.

Hook · 5 min

  • Cut a pizza or a strip of paper unevenly and ask whether the pieces are really halves or quarters.
  • Share the objective: Predict the size of a product: multiplying as scaling. Read the success criteria together.

I do: model it · 10 min

  • Work through the example out loud, saying why you do each step, not just what you do.
  • Example: Without calculating: is 89 × 5/3 less than, greater than or equal to 89?
  • Step 1: 5/3 > 1
  • Step 2: greater than 89
  • Answer: greater than 89
  • Pause after each step and ask a student to say what comes next.

We do: guided practice · 10 min

  • Do these together. Students try each step on whiteboards before you reveal it.
  • Use the hints as prompts rather than giving the answer.
  1. Without calculating: is 21 × 5/8 less than, greater than or equal to 21? (less than 21 / greater than 21 / equal to 21) → less than 21Prompt: Is 5/8 less than 1, more than 1, or exactly 1?
  2. Which product is greatest? 44 × 3/4, 44 × 1/2, 44 × 3/2 (44 × 3/4 / 44 × 1/2 / 44 × 3/2) → 44 × 3/2Prompt: Every product uses 44, so compare the fractions.

You do: independent practice · 10 min

  • Students work on the student sheet. Circulate and check the first two answers of every student early.
  • Students who finish: write a question of their own for a partner, with the answer.

The 8 questions are on the student sheet below, with answers in the key.

Exit ticket · 5 min

  • Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
  1. Which product is greatest? 49 × 3/2, 49 × 3/4, 49 × 5/4 (49 × 3/2 / 49 × 3/4 / 49 × 5/4) → 49 × 3/2Prompt: Every product uses 49, so compare the fractions.
  2. Without calculating: is 19 × 3/7 less than, greater than or equal to 19? (less than 19 / greater than 19 / equal to 19) → less than 19Prompt: Is 3/7 less than 1, more than 1, or exactly 1?

Watch out for

  • Thinking a bigger denominator means a bigger fraction (1/8 > 1/4).
  • Adding the denominators when adding fractions (1/2 + 1/3 = 2/5).

Support and stretch

Support

  • Review first: Multiply fractions.
  • Use concrete materials: fraction strips or a fraction wall.
  • Give the first step of each question, or a partly worked example to finish.
  • Pair with a confident partner for the guided practice.

Stretch

  • Explain a common mistake in writing and how to fix it.
  • Write a word problem that uses today's skill, then solve a partner's.

Homework and more practice

Free online practice with hints and printable worksheets for this skill: eurekami.com/math/grade-5.

Free lesson plan from eurekami.com/lesson-plan-builder

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Predict the size of a product: multiplying as scaling

Name

Date

Score/ 8

  1. Question 1

    Without calculating: is 33 × 5/3 less than, greater than or equal to 33?

    • A. less than 33
    • B. greater than 33
    • C. equal to 33
  2. Question 2

    Which product is greatest? 30 × 5/4, 30 × 3/4, 30 × 1/2

    • A. 30 × 5/4
    • B. 30 × 3/4
    • C. 30 × 1/2
  3. Question 3

    Without calculating: is 59 × 5/5 less than, greater than or equal to 59?

    • A. less than 59
    • B. greater than 59
    • C. equal to 59
  4. Question 4

    Which product is greatest? 48 × 3/2, 48 × 3/4, 48 × 7/8

    • A. 48 × 3/2
    • B. 48 × 3/4
    • C. 48 × 7/8
  5. Question 5

    Without calculating: is 87 × 7/4 less than, greater than or equal to 87?

    • A. less than 87
    • B. greater than 87
    • C. equal to 87
  6. Question 6

    Which product is greatest? 39 × 3/2, 39 × 7/8, 39 × 3/4

    • A. 39 × 3/2
    • B. 39 × 7/8
    • C. 39 × 3/4
  7. Question 7

    Without calculating: is 80 × 3/3 less than, greater than or equal to 80?

    • A. less than 80
    • B. greater than 80
    • C. equal to 80
  8. Question 8

    Which product is greatest? 44 × 5/4, 44 × 1/2, 44 × 3/4

    • A. 44 × 5/4
    • B. 44 × 1/2
    • C. 44 × 3/4

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Answer key: Predict the size of a product: multiplying as scaling

  1. 1. B. greater than 33

  2. 2. A. 30 × 5/4

  3. 3. C. equal to 59

  4. 4. A. 48 × 3/2

  5. 5. B. greater than 87

  6. 6. A. 39 × 3/2

  7. 7. C. equal to 80

  8. 8. A. 44 × 5/4