CBSE Class 10 Real Numbers MCQs – Fundamental Theorem of Arithmetic & HCF LCM
CBSE Class 10 Real Numbers MCQs – Fundamental Theorem of Arithmetic & HCF LCM
Class: 10 | Subject: Mathematics | Chapter 1: Real Numbers
As per Latest CBSE Board Examination Pattern
These MCQs are strictly designed according to CBSE curriculum and NCERT textbooks.
Q1. Express 540 as a product of prime factors.
Answer: A
Explanation: 540 = 54 × 10 = (2 × 3³) × (2 × 5) = 2² × 3³ × 5.
Explanation: 540 = 54 × 10 = (2 × 3³) × (2 × 5) = 2² × 3³ × 5.
Q2. The HCF of 306 and 657 is:
Answer: A
Explanation: Using Euclid’s Division Algorithm, HCF(657,306)=9.
Explanation: Using Euclid’s Division Algorithm, HCF(657,306)=9.
Q3. The LCM of 72 and 120 is:
Answer: A
Explanation: 72=2³×3², 120=2³×3×5 → LCM=2³×3²×5=360.
Explanation: 72=2³×3², 120=2³×3×5 → LCM=2³×3²×5=360.
Q4. If HCF(65,117) = 13, then LCM is:
Answer: B
Explanation: Product = 65×117=7605. LCM=(7605÷13)=585.
Explanation: Product = 65×117=7605. LCM=(7605÷13)=585.
Q5. The decimal expansion of 13/1600 is:
Answer: A
Explanation: 1600=2⁶×5². Since denominator has only 2 and 5, decimal is terminating.
Explanation: 1600=2⁶×5². Since denominator has only 2 and 5, decimal is terminating.
Q6. √3 is irrational because:
Answer: A
Explanation: √3 cannot be written in p/q form where q≠0.
Explanation: √3 cannot be written in p/q form where q≠0.
Q7. The HCF of two numbers is 12 and their product is 1800. Their LCM is:
Answer: B
Explanation: LCM = Product ÷ HCF = 1800 ÷ 12 = 150.
Explanation: LCM = Product ÷ HCF = 1800 ÷ 12 = 150.
Q8. Which of the following is irrational?
Answer: C
Explanation: √7 cannot be written as p/q.
Explanation: √7 cannot be written as p/q.
Q9. Using Euclid’s Division Lemma, 135 = 18 × 7 + ?
Answer: A
Explanation: 18×7=126; 135−126=9.
Explanation: 18×7=126; 135−126=9.
Q10. The number 2⁴×3²×5 is divisible by:
Answer: D
Explanation: Contains 3² (9), 5² not present but 5¹ so not 25? Wait correction → contains 2⁴ (16), 3² (9), 5¹. So divisible by 9 and 8 but not 25. Correct answer should be C only.
Explanation: Contains 3² (9), 5² not present but 5¹ so not 25? Wait correction → contains 2⁴ (16), 3² (9), 5¹. So divisible by 9 and 8 but not 25. Correct answer should be C only.
Q10. The number 2⁴×3²×5 is divisible by:
Answer: D
Explanation: 3² gives 9 and 2³ gives 8. But only one 5 is present, so not divisible by 25.
Explanation: 3² gives 9 and 2³ gives 8. But only one 5 is present, so not divisible by 25.
Q11. The LCM of two coprime numbers is equal to:
Answer: B
Explanation: For coprime numbers, HCF=1 → LCM=Product.
Explanation: For coprime numbers, HCF=1 → LCM=Product.
Q12. The HCF of two consecutive even numbers is:
Answer: B
Explanation: Consecutive even numbers share only 2 as common factor.
Explanation: Consecutive even numbers share only 2 as common factor.
Q13. The decimal expansion of 7/11 is:
Answer: B
Explanation: Denominator has prime other than 2 or 5 → repeating decimal.
Explanation: Denominator has prime other than 2 or 5 → repeating decimal.
Q14. If HCF=16 and one number=64, the other number=48. Find LCM.
Answer: C
Explanation: LCM = (64×48)/16 = 192.
Explanation: LCM = (64×48)/16 = 192.
Q15. Which of the following is a rational number?
Answer: C
Explanation: 0.375 is terminating decimal = 3/8.
Explanation: 0.375 is terminating decimal = 3/8.
Q16. The HCF of 867 and 255 is:
Answer: A
Explanation: Using Euclid’s Algorithm repeatedly → HCF=51.
Explanation: Using Euclid’s Algorithm repeatedly → HCF=51.
Q17. The smallest number divisible by 12, 15 and 20 is:
Answer: A
Explanation: LCM(12,15,20)=60.
Explanation: LCM(12,15,20)=60.
Q18. √5 × √5 equals:
Answer: A
Explanation: √a × √a = a.
Explanation: √a × √a = a.
Q19. The number 2ⁿ × 5ᵐ has terminating decimal expansion when written as fraction if:
Answer: C
Explanation: Only 2 and 5 prime factors give terminating decimal.
Explanation: Only 2 and 5 prime factors give terminating decimal.
Q20. If two numbers are 135 and 225, their HCF is:
Answer: B
Explanation: 135=3³×5; 225=3²×5² → HCF=3²×5=45.
Explanation: 135=3³×5; 225=3²×5² → HCF=3²×5=45.
