CBSE Class 10 Mathematics Basic sample paper 2025-26: question 21(B)
From the official CBSE sample question paper for 2025-26, section B, question 21(B), for 2 marks. Try it first; the hints and our step-by-step solution are below.
Q21(B) · 2 marks · Very short answerReal Numbers
Find the smallest number which is divisible by both 306 and 657.
Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2025-26.
Hints
Open one hint at a time and try again before the next.
Hint 1
The smallest number that both numbers divide exactly is a well-known idea: HCF or LCM?
Hint 2
Write 306 and 657 as products of primes and take each prime with its highest power.
Step-by-step solution
Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.
- ½ mark
The smallest number divisible by both 306 and 657 is their LCM.
- 1 mark
Prime factorisation: and
- ½ mark
LCM . So the required number is 22338.
Answer: 22338
Where the marks are
- Recognises that the required number is the LCM (½ mark)
- Correct prime factorisations of 306 and 657 (1 mark)
- LCM = 22338 (½ mark)
Revise the chapter
- Chapter: Real Numbers (notes, formulas, where marks are lost and every past question)
- Topic: HCF and LCM by Prime Factorisation
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