Question 1
EasyOriginal questionWhat is the least common multiple of 12, 18 and 24?
Show the answer and explanation
CorrectNot quiteAnswer B
Correct answer: B
Explanation
Write each number as a product of prime factors: , and .
The LCM takes the highest power of each prime that appears anywhere: from 24 and from 18.
So the LCM is .
Check: , and , all whole numbers.
Worth noting
144 and 216 are common multiples too, but the question asks for the least one. Multiplying the numbers together always gives a common multiple and almost never the smallest.
- Concept
- LCM by prime factorisation
- Typical timeTypical
- 45 s
- Your timeYours
- —
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Ten questions from HCF & LCM, at your own pace.