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MathsAges 13-15

Lowest common multiple (LCM)

Find the lowest common multiple (LCM) shared by two whole numbers. Review suitability for your learners before teaching.

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Age band:Ages 10-12Ages 13-15

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Worksheet StudioPractice pack · Ages 13-15

Lowest common multiple (LCM)

Take your time. Show your thinking.

  1. 1. What is the lowest common multiple (LCM) of 15 and 21?

    15 · 21 · Lowest common multiple (LCM)

  2. 2. What is the lowest common multiple (LCM) of 10 and 35?

    10 · 35 · Lowest common multiple (LCM)

  3. 3. What is the lowest common multiple (LCM) of 30 and 42?

    30 · 42 · Lowest common multiple (LCM)

  4. 4. What is the lowest common multiple (LCM) of 12 and 28?

    12 · 28 · Lowest common multiple (LCM)

  5. 5. What is the lowest common multiple (LCM) of 21 and 49?

    21 · 49 · Lowest common multiple (LCM)

  6. 6. What is the lowest common multiple (LCM) of 12 and 18?

    12 · 18 · Lowest common multiple (LCM)

  7. 7. What is the lowest common multiple (LCM) of 10 and 25?

    10 · 25 · Lowest common multiple (LCM)

  8. 8. What is the lowest common multiple (LCM) of 24 and 84?

    24 · 84 · Lowest common multiple (LCM)

  9. 9. What is the lowest common multiple (LCM) of 16 and 20?

    16 · 20 · Lowest common multiple (LCM)

  10. 10. What is the lowest common multiple (LCM) of 25 and 35?

    25 · 35 · Lowest common multiple (LCM)

  11. 11. What is the lowest common multiple (LCM) of 18 and 42?

    18 · 42 · Lowest common multiple (LCM)

  12. 12. What is the lowest common multiple (LCM) of 4 and 6?

    4 · 6 · Lowest common multiple (LCM)
12 questions · Seed 70 · Age guidance, not curriculum certification
View the answer key
Worksheet StudioAnswer key · Ages 13-15

Lowest common multiple (LCM)

Answers and reasoning. Review before teaching.

  1. 1. What is the lowest common multiple (LCM) of 15 and 21?

    105

    The highest common factor of 15 and 21 is 3, so LCM = (15 × 21) ÷ 3 = 105.

  2. 2. What is the lowest common multiple (LCM) of 10 and 35?

    70

    The highest common factor of 10 and 35 is 5, so LCM = (10 × 35) ÷ 5 = 70.

  3. 3. What is the lowest common multiple (LCM) of 30 and 42?

    210

    The highest common factor of 30 and 42 is 6, so LCM = (30 × 42) ÷ 6 = 210.

  4. 4. What is the lowest common multiple (LCM) of 12 and 28?

    84

    The highest common factor of 12 and 28 is 4, so LCM = (12 × 28) ÷ 4 = 84.

  5. 5. What is the lowest common multiple (LCM) of 21 and 49?

    147

    The highest common factor of 21 and 49 is 7, so LCM = (21 × 49) ÷ 7 = 147.

  6. 6. What is the lowest common multiple (LCM) of 12 and 18?

    36

    The highest common factor of 12 and 18 is 6, so LCM = (12 × 18) ÷ 6 = 36.

  7. 7. What is the lowest common multiple (LCM) of 10 and 25?

    50

    The highest common factor of 10 and 25 is 5, so LCM = (10 × 25) ÷ 5 = 50.

  8. 8. What is the lowest common multiple (LCM) of 24 and 84?

    168

    The highest common factor of 24 and 84 is 12, so LCM = (24 × 84) ÷ 12 = 168.

  9. 9. What is the lowest common multiple (LCM) of 16 and 20?

    80

    The highest common factor of 16 and 20 is 4, so LCM = (16 × 20) ÷ 4 = 80.

  10. 10. What is the lowest common multiple (LCM) of 25 and 35?

    175

    The highest common factor of 25 and 35 is 5, so LCM = (25 × 35) ÷ 5 = 175.

  11. 11. What is the lowest common multiple (LCM) of 18 and 42?

    126

    The highest common factor of 18 and 42 is 6, so LCM = (18 × 42) ÷ 6 = 126.

  12. 12. What is the lowest common multiple (LCM) of 4 and 6?

    12

    The highest common factor of 4 and 6 is 2, so LCM = (4 × 6) ÷ 2 = 12.

12 questions · Seed 70 · Age guidance, not curriculum certification
Worksheet StudioPractice pack · Ages 13-15

Lowest common multiple (LCM)

Take your time. Show your thinking.

  1. 1. What is the lowest common multiple (LCM) of 15 and 21?

    15 · 21 · Lowest common multiple (LCM)

  2. 2. What is the lowest common multiple (LCM) of 10 and 35?

    10 · 35 · Lowest common multiple (LCM)

  3. 3. What is the lowest common multiple (LCM) of 30 and 42?

    30 · 42 · Lowest common multiple (LCM)

  4. 4. What is the lowest common multiple (LCM) of 12 and 28?

    12 · 28 · Lowest common multiple (LCM)

  5. 5. What is the lowest common multiple (LCM) of 21 and 49?

    21 · 49 · Lowest common multiple (LCM)

  6. 6. What is the lowest common multiple (LCM) of 12 and 18?

    12 · 18 · Lowest common multiple (LCM)

  7. 7. What is the lowest common multiple (LCM) of 10 and 25?

    10 · 25 · Lowest common multiple (LCM)

  8. 8. What is the lowest common multiple (LCM) of 24 and 84?

    24 · 84 · Lowest common multiple (LCM)

  9. 9. What is the lowest common multiple (LCM) of 16 and 20?

    16 · 20 · Lowest common multiple (LCM)

  10. 10. What is the lowest common multiple (LCM) of 25 and 35?

    25 · 35 · Lowest common multiple (LCM)

  11. 11. What is the lowest common multiple (LCM) of 18 and 42?

    18 · 42 · Lowest common multiple (LCM)

  12. 12. What is the lowest common multiple (LCM) of 4 and 6?

    4 · 6 · Lowest common multiple (LCM)
12 questions · Seed 70 · Age guidance, not curriculum certification
Worksheet StudioAnswer key · Ages 13-15

Lowest common multiple (LCM)

Answers and reasoning. Review before teaching.

  1. 1. What is the lowest common multiple (LCM) of 15 and 21?

    105

    The highest common factor of 15 and 21 is 3, so LCM = (15 × 21) ÷ 3 = 105.

  2. 2. What is the lowest common multiple (LCM) of 10 and 35?

    70

    The highest common factor of 10 and 35 is 5, so LCM = (10 × 35) ÷ 5 = 70.

  3. 3. What is the lowest common multiple (LCM) of 30 and 42?

    210

    The highest common factor of 30 and 42 is 6, so LCM = (30 × 42) ÷ 6 = 210.

  4. 4. What is the lowest common multiple (LCM) of 12 and 28?

    84

    The highest common factor of 12 and 28 is 4, so LCM = (12 × 28) ÷ 4 = 84.

  5. 5. What is the lowest common multiple (LCM) of 21 and 49?

    147

    The highest common factor of 21 and 49 is 7, so LCM = (21 × 49) ÷ 7 = 147.

  6. 6. What is the lowest common multiple (LCM) of 12 and 18?

    36

    The highest common factor of 12 and 18 is 6, so LCM = (12 × 18) ÷ 6 = 36.

  7. 7. What is the lowest common multiple (LCM) of 10 and 25?

    50

    The highest common factor of 10 and 25 is 5, so LCM = (10 × 25) ÷ 5 = 50.

  8. 8. What is the lowest common multiple (LCM) of 24 and 84?

    168

    The highest common factor of 24 and 84 is 12, so LCM = (24 × 84) ÷ 12 = 168.

  9. 9. What is the lowest common multiple (LCM) of 16 and 20?

    80

    The highest common factor of 16 and 20 is 4, so LCM = (16 × 20) ÷ 4 = 80.

  10. 10. What is the lowest common multiple (LCM) of 25 and 35?

    175

    The highest common factor of 25 and 35 is 5, so LCM = (25 × 35) ÷ 5 = 175.

  11. 11. What is the lowest common multiple (LCM) of 18 and 42?

    126

    The highest common factor of 18 and 42 is 6, so LCM = (18 × 42) ÷ 6 = 126.

  12. 12. What is the lowest common multiple (LCM) of 4 and 6?

    12

    The highest common factor of 4 and 6 is 2, so LCM = (4 × 6) ÷ 2 = 12.

12 questions · Seed 70 · Age guidance, not curriculum certification