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Math lesson plan · 4th grade (Year 5 in England) · 60 minutes

Find factor pairs of a number

Number sense

CCSS 4.OA.B.4England: Y5 Multiplication and division

Objective and success criteria

Students will: Find factor pairs of a number.

  • 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: Factors, multiples, primes

Leads to: Recognise multiples of a number; Prime or composite?; Common factors of two numbers

Materials: Place value chart, Base-ten blocks or a number line, Mini whiteboards and pens, Printed student sheet (below).

Warm-up · 6 min

  • Quick retrieval from earlier learning (Factors, multiples, primes). Students answer on mini whiteboards.
  • Show answers together and note who needs support in the main task.
  1. Which number is a factor of 42? (4 / 11 / 8 / 14) → 14Prompt: A factor divides the number exactly, with no remainder.
  2. Is 26 prime or composite? (Prime / Composite) → CompositePrompt: A prime number has exactly two factors: 1 and itself.
  3. What is the 7th multiple of 3? (The 1st multiple is 3.) → 21Prompt: Multiples of 3: 3, 6, 9, …

Hook · 6 min

  • Show a number in the news or a price tag and ask what each digit is worth.
  • Share the objective: Find factor pairs of a number. Read the success criteria together.

I do: model it · 12 min

  • Work through the example out loud, saying why you do each step, not just what you do.
  • Example: 6 × __ = 60. Complete the factor pair.
  • Step 1: 60 ÷ 6 = 10
  • Step 2: 6 × 10 = 60
  • Answer: 10
  • Pause after each step and ask a student to say what comes next.

We do: guided practice · 12 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. 3 × __ = 54. Complete the factor pair. → 18Prompt: What do you multiply 3 by to get 54?
  2. How many factors does 18 have? (Count 1 and 18 too.) → 6Prompt: List factor pairs: 1 × ?, 2 × ?, 3 × ? …

You do: independent practice · 17 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 · 7 min

  • Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
  1. How many factors does 30 have? (Count 1 and 30 too.) → 8Prompt: List factor pairs: 1 × ?, 2 × ?, 3 × ? …
  2. Jamal is arranging 60 photos in a rectangle with no gaps. Which layout works? (6 × 11 / 7 × 10 / 6 × 10 / 30 × 3) → 6 × 10Prompt: Rows × columns must equal 60.

Watch out for

  • Reading 1,045 as one thousand four hundred five: point to each place and say its value.
  • Thinking a longer number is always bigger, even with decimals (0.45 vs 0.5).

Support and stretch

Support

  • Review first: Factors, multiples, primes.
  • Use concrete materials: place value chart.
  • 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: Recognise multiples of a number; Prime or composite?; Common factors of two numbers.
  • 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-4.

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

eurekami

Find factor pairs of a number

Name

Date

Score/ 8

  1. Question 1

    How many factors does 20 have? (Count 1 and 20 too.)

    Answer

  2. Question 2

    2 × __ = 20. Complete the factor pair.

    Answer

  3. Question 3

    Lucia is arranging 30 photos in a rectangle with no gaps. Which layout works?

    • A. 15 × 3
    • B. 3 × 10
    • C. 4 × 10
    • D. 3 × 11
  4. Question 4

    How many factors does 48 have? (Count 1 and 48 too.)

    Answer

  5. Question 5

    6 × __ = 48. Complete the factor pair.

    Answer

  6. Question 6

    Liam is arranging 36 photos in a rectangle with no gaps. Which layout works?

    • A. 3 × 18
    • B. 2 × 18
    • C. 2 × 19
    • D. 18 × 3
  7. Question 7

    How many factors does 40 have? (Count 1 and 40 too.)

    Answer

  8. Question 8

    8 × __ = 64. Complete the factor pair.

    Answer

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Answer key: Find factor pairs of a number

  1. 1. 6

  2. 2. 10

  3. 3. B. 3 × 10

  4. 4. 10

  5. 5. 8

  6. 6. B. 2 × 18

  7. 7. 8

  8. 8. 8