LCM and HCF questions and answers

20 questions in 2 online tests, each with its answer and a worked solution.

Start Test 1

LCM and HCF: key points

The LCM of a set of numbers is the smallest number divisible by all of them; the HCF is the largest number that divides all of them.

  • Product of two numbers = their LCM × their HCF.
  • "When will they ring or meet together again" asks for the LCM.
  • "Greatest number that divides" asks for the HCF.
  • Least number leaving remainder r when divided by a, b, c = LCM(a, b, c) + r.

How to practise LCM and HCF

Start with the key points, then take one LCM and HCF test without rushing. Review every explanation, note the steps you missed and repeat the topic against the clock. APTITUDE TESTER has 20 questions in 2 tests for this topic.

  • Read the method before attempting a timed test.
  • Record mistakes by type: concept, calculation or time management.
  • Return to the hardest questions after a day and try them again.

Continue with another Quantitative topic when your accuracy is steady.

LCM and HCF online tests

Sample LCM and HCF questions

  1. 1. Find the LCM of 8, 10, 12.
    1. 2
    2. 120
    3. 180
    4. 960

    Reference: q-8b0ca6b4-27 · Report this question

    Show answer and solution

    Answer: B. 120

    LCM of 8, 10, 12 = 120, the smallest number divisible by all three.
  2. 2. Find the HCF of 55 and 99.
    1. 495
    2. 11
    3. 9
    4. 10

    Reference: q-ffa7d51a-27 · Report this question

    Show answer and solution

    Answer: B. 11

    55 = 11 × 5 and 99 = 11 × 9, where 5 and 9 have no common factor. HCF = 11.
  3. 3. The HCF and LCM of two numbers are 9 and 54. If one of the numbers is 18, find the other.
    1. 27
    2. 45
    3. 54
    4. 6

    Reference: q-b7259ec6-90 · Report this question

    Show answer and solution

    Answer: A. 27

    Product of the numbers = HCF × LCM. Other number = 9 × 54 / 18 = 27.

See all the questions of Test 1

LCM and HCF: questions people ask

How many LCM and HCF questions are there?

There are 20 LCM and HCF questions in 2 tests. Each test has its own page that lists the questions with their answers and solutions.

How long does a LCM and HCF test take?

A test of 10 questions has a time limit of 15 minutes, which is 90 seconds a question.

Is there negative marking?

Rules vary by set. The rules screen shows the time limit, marks, any wrong-answer penalty and calculator permission before you begin. Feedback mode has no time limit or negative marking.

Can I practise LCM and HCF without a time limit?

Yes. Choose practice mode: there is no clock, and the answer and solution appear as soon as you select an option.