Practice MCQs on Divisibility and Prime Factors
CBSE Class 6 Mathematics – Practice MCQs with Answers & Explanations
Chapter 5: Prime Time
Topic: Divisibility and Prime Factors
Strictly Based on NCERT | Latest CBSE Curriculum
CBSE Board Examination Preparation – Class 6 Mathematics
1. Which of the following numbers is divisible by 2?
Correct Answer: B
Explanation: A number divisible by 2 must end in 0, 2, 4, 6, or 8. 728 ends in 8, so it is divisible by 2.
Explanation: A number divisible by 2 must end in 0, 2, 4, 6, or 8. 728 ends in 8, so it is divisible by 2.
2. Which number is divisible by 3?
Correct Answer: A
Explanation: Sum of digits of 123 = 1+2+3=6. Since 6 is divisible by 3, 123 is divisible by 3.
Explanation: Sum of digits of 123 = 1+2+3=6. Since 6 is divisible by 3, 123 is divisible by 3.
3. Which number is divisible by 5?
Correct Answer: B
Explanation: A number divisible by 5 ends in 0 or 5. 450 ends in 0.
Explanation: A number divisible by 5 ends in 0 or 5. 450 ends in 0.
4. Which number is divisible by both 2 and 3?
Correct Answer: A
Explanation: 18 is even (divisible by 2). Sum of digits = 1+8=9, divisible by 3. So 18 is divisible by both.
Explanation: 18 is even (divisible by 2). Sum of digits = 1+8=9, divisible by 3. So 18 is divisible by both.
5. Prime factorization of 28 is:
Correct Answer: C
Explanation: 28 ÷2=14, 14 ÷2=7 → 2×2×7.
Explanation: 28 ÷2=14, 14 ÷2=7 → 2×2×7.
6. Which of the following is a prime number?
Correct Answer: B
Explanation: 29 has only two factors: 1 and 29. Others are divisible by 3 or 5.
Explanation: 29 has only two factors: 1 and 29. Others are divisible by 3 or 5.
7. Prime factorization of 42:
Correct Answer: A
Explanation: 42 ÷2=21, 21=3×7 → 2×3×7.
Explanation: 42 ÷2=21, 21=3×7 → 2×3×7.
8. Which number is divisible by 9?
Correct Answer: C
Explanation: Sum of digits of 237 = 2+3+7=12 (not divisible by 9). Wait check carefully.
Correction: 234 → 2+3+4=9 → divisible by 9.
Correct Answer: A.
Explanation: Sum of digits of 237 = 2+3+7=12 (not divisible by 9). Wait check carefully.
Correction: 234 → 2+3+4=9 → divisible by 9.
Correct Answer: A.
9. Prime factorization of 45:
Correct Answer: A
Explanation: 45 ÷3=15, 15=3×5 → 3×3×5.
Explanation: 45 ÷3=15, 15=3×5 → 3×3×5.
10. Which of the following is not divisible by 3?
Correct Answer: C
Explanation: 2+5+1=8 (not divisible by 3).
Explanation: 2+5+1=8 (not divisible by 3).
11. Prime factorization of 60:
Correct Answer: A
60÷2=30÷2=15=3×5.
60÷2=30÷2=15=3×5.
12. Which number is divisible by both 4 and 5?
Correct Answer: A
40 ends in 0 (divisible by 5) and last two digits 40 divisible by 4.
40 ends in 0 (divisible by 5) and last two digits 40 divisible by 4.
13. Prime factorization of 81:
Correct Answer: A
81=9×9=3×3×3×3.
81=9×9=3×3×3×3.
14. Which number is divisible by 10?
Correct Answer: B
Number ending in 0 is divisible by 10.
Number ending in 0 is divisible by 10.
15. Prime factorization of 32:
Correct Answer: A
Divide repeatedly by 2.
Divide repeatedly by 2.
16. Which number is divisible by 6?
Correct Answer: A
Divisible by 2 and 3.
Divisible by 2 and 3.
17. Prime factorization of 72:
Correct Answer: A
72÷2=36÷2=18÷2=9=3×3.
72÷2=36÷2=18÷2=9=3×3.
18. Which number is divisible by 8?
Correct Answer: A
Last three digits 216 ÷8=27.
Last three digits 216 ÷8=27.
19. Prime factorization of 54:
Correct Answer: A
54÷2=27=3×3×3.
54÷2=27=3×3×3.
20. Which number is divisible by 11?
Correct Answer: A
121=11×11.
121=11×11.
