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Math lesson plan · 3rd grade (Year 4 in England) · 45 minutes

Find the unknown in multiplication and division equations

Multiplication and division

CCSS 3.OA.A.4England: Y3 Multiplication and division

Objective and success criteria

Students will: Find the unknown in multiplication and division equations.

  • 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: Multiplication and division fact families

Leads to: Solve equations with a letter for the unknown

Materials: Counters for arrays, Multiplication grid, Base-ten blocks, Mini whiteboards and pens, Printed student sheet (below).

Warm-up · 5 min

  • Quick retrieval from earlier learning (Multiplication and division fact families). Students answer on mini whiteboards.
  • Show answers together and note who needs support in the main task.
  1. Which fact belongs in the same family as 10 × 6 = 60? (10 + 6 = 16 / 60 ÷ 6 = 10 / 60 − 10 = 50 / 60 ÷ 11 = 6) → 60 ÷ 6 = 10Prompt: A fact family uses the same three numbers: 10, 6 and 60.
  2. Given 12 × 4 = 48, what is 48 ÷ 4? → 12Prompt: Division undoes multiplication.
  3. Which fact belongs in the same family as 6 × 2 = 12? (12 ÷ 7 = 2 / 6 + 2 = 8 / 12 ÷ 2 = 6 / 12 − 6 = 6) → 12 ÷ 2 = 6Prompt: A fact family uses the same three numbers: 6, 2 and 12.

Hook · 5 min

  • Show an array of chairs, eggs or windows and ask how many there are without counting one by one.
  • Share the objective: Find the unknown in multiplication and division equations. 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: What number does â–¢ stand for? 30 = â–¢ × 10
  • Step 1: 30 = 3 × 10
  • Step 2: 3
  • Answer: 3
  • 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. What number does ▢ stand for? 12 ÷ ▢ = 6 → 2Prompt: Read the equation as a sentence: what times or divided by what?
  2. Arjun thinks of a number and multiplies it by 4. The answer is 32. What was the number? → 8Prompt: Write it as ▢ × 4 = 32.

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. Sofia thinks of a number and multiplies it by 6. The answer is 54. What was the number? → 9Prompt: Write it as ▢ × 6 = 54.
  2. What number does ▢ stand for? 14 ÷ ▢ = 2 → 7Prompt: Read the equation as a sentence: what times or divided by what?

Watch out for

  • Thinking multiplying always makes a number bigger.
  • Dropping a zero in long multiplication when moving to the tens row.

Support and stretch

Support

  • Review first: Multiplication and division fact families.
  • Use concrete materials: counters for arrays.
  • Give the first step of each question, or a partly worked example to finish.
  • Pair with a confident partner for the guided practice.

Stretch

  • Move on to: Solve equations with a letter for the unknown.
  • 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-3.

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

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Find the unknown in multiplication and division equations

Name

Date

Score/ 8

  1. Question 1

    Arjun thinks of a number and multiplies it by 7. The answer is 63. What was the number?

    Answer

  2. Question 2

    What number does ▢ stand for? 12 ÷ ▢ = 2

    Answer

  3. Question 3

    Daniel thinks of a number and multiplies it by 9. The answer is 81. What was the number?

    Answer

  4. Question 4

    What number does ▢ stand for? 20 ÷ ▢ = 4

    Answer

  5. Question 5

    Hana thinks of a number and multiplies it by 9. The answer is 36. What was the number?

    Answer

  6. Question 6

    What number does ▢ stand for? 60 ÷ ▢ = 10

    Answer

  7. Question 7

    Sam thinks of a number and multiplies it by 6. The answer is 36. What was the number?

    Answer

  8. Question 8

    What number does ▢ stand for? 50 ÷ ▢ = 5

    Answer

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Answer key: Find the unknown in multiplication and division equations

  1. 1. 9

  2. 2. 6

  3. 3. 9

  4. 4. 5

  5. 5. 4

  6. 6. 6

  7. 7. 6

  8. 8. 10