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

Common multiples and the lowest common multiple

Number sense

CCSS 6.NS.B.4England: Y6 Number – multiplication and division

Objective and success criteria

Students will: Common multiples and the lowest common multiple.

  • 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: Recognise multiples of a number

Leads to: the next skill in this area.

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

Warm-up · 5 min

  • Quick retrieval from earlier learning (Recognise multiples of a number). Students answer on mini whiteboards.
  • Show answers together and note who needs support in the main task.
  1. Which is a multiple of 4? (58 / 61 / 63 / 60) → 60Prompt: A multiple of 4 is in the 4 times table (or beyond it).
  2. How many multiples of 11 are there from 1 to 58? → 5Prompt: What is the biggest multiple of 11 that is not more than 58?
  3. Ines says 129 is a multiple of 8. True or false? (true / false) → falsePrompt: Divide 129 by 8.

Hook · 5 min

  • Show a number in the news or a price tag and ask what each digit is worth.
  • Share the objective: Common multiples and the lowest common multiple. 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 is the lowest common multiple of 3 and 4?
  • Step 1: Multiples of 4: 4, 8, 12, 16, 20
  • Step 2: 12
  • Answer: 12
  • 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 is the lowest common multiple of 5 and 6? → 30Prompt: List multiples of 6: 6, 12, 18, …
  2. Two buses leave the station together at 10:00. One leaves every 6 minutes and the other every 10 minutes. After how many minutes do they next leave together? → 30Prompt: You need a time that is in both lists of departure times.

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. What is the lowest common multiple of 6 and 9? → 18Prompt: List multiples of 9: 9, 18, 27, …
  2. Two buses leave the station together at 7:00. One leaves every 10 minutes and the other every 15 minutes. After how many minutes do they next leave together? → 30Prompt: You need a time that is in both lists of departure times.

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: Recognise multiples of a number.
  • 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

  • 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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Common multiples and the lowest common multiple

Name

Date

Score/ 8

  1. Question 1

    What is the lowest common multiple of 3 and 5?

    Answer

  2. Question 2

    Two buses leave the station together at 8:00. One leaves every 12 minutes and the other every 20 minutes. After how many minutes do they next leave together?

    Answer

  3. Question 3

    What is the lowest common multiple of 2 and 3?

    Answer

  4. Question 4

    Two buses leave the station together at 7:00. One leaves every 6 minutes and the other every 10 minutes. After how many minutes do they next leave together?

    Answer

  5. Question 5

    What is the lowest common multiple of 4 and 10?

    Answer

  6. Question 6

    Two buses leave the station together at 8:00. One leaves every 6 minutes and the other every 8 minutes. After how many minutes do they next leave together?

    Answer

  7. Question 7

    What is the lowest common multiple of 6 and 10?

    Answer

  8. Question 8

    Two buses leave the station together at 9:00. One leaves every 9 minutes and the other every 12 minutes. After how many minutes do they next leave together?

    Answer

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Answer key: Common multiples and the lowest common multiple

  1. 1. 15

  2. 2. 60

  3. 3. 6

  4. 4. 30

  5. 5. 20

  6. 6. 24

  7. 7. 30

  8. 8. 36