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HCF and LCM

Quantitative Aptitude · Maths Bookwise · Number System

Useful for: SSC CGL

BOOK-GUIDED ORIGINAL SSC MATHS PRACTICE — HCF and LCM

FOUNDATION

HCF(a,b) × LCM(a,b) = a × b for positive integers.

METHOD

Identify the quantities given, choose the exact relationship, calculate in the same unit, then check the answer against the question.

WORKED EXAMPLE 1

Find the LCM of 27 and 6.

HCF(27,6)=3. LCM = 27×6/3 = 54.

WORKED EXAMPLE 2

Find the LCM of 204 and 24.

HCF(204,24)=12. LCM = 204×24/12 = 408.

IMPORTANT EXCEPTION / COMMON TRAP

The identity holds for exactly two given positive integers.

QUICK REVISION

HCF(a,b) × LCM(a,b) = a × b for positive integers.

SEE MORE: https://study.kundali-iq.com/ssc-maths/hcf/

For complete timed maths practice, use SSC CGL Test Series → New Maths 100 Mixed Sets or Chapter-wise sets. These are independent original questions, not copied previous-year questions.

Practice MCQs

Find the LCM of 27 and 6.
1. 54
2. 51
3. 57
4. 60
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Answer: (a) 54. HCF(27,6)=3. LCM = 27×6/3 = 54.
Find the LCM of 204 and 24.
1. 462
2. 381
3. 408
4. 435
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Show answer
Answer: (c) 408. HCF(204,24)=12. LCM = 204×24/12 = 408.
Find the LCM of 24 and 64.
1. 180
2. 192
3. 216
4. 204
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Answer: (b) 192. HCF(24,64)=8. LCM = 24×64/8 = 192.
Find the LCM of 266 and 252.
1. 4469
2. 5107
3. 4788
4. 5426
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Answer: (c) 4788. HCF(266,252)=14. LCM = 266×252/14 = 4788.
What is the least common multiple (LCM) of 12 and 18
1. 6
2. 36
3. 24
4. 72
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Answer: (b) 36. Prime factors: 12 = 2² × 3 and 18 = 2 × 3²; LCM = 2² × 3² = 36.

HCF and LCM

Practice MCQs

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