SSC CGL Number System MCQs with Answers & Tricks 2026
Practice the best SSC CGL Number System MCQs with answers, shortcut tricks, detailed explanations, and SSC exam-level questions for 2026 preparation.
1. Which of the following numbers is divisible by 11?
A. 34562 B. 56782
C. 72831 D. 91872
Correct Answer: B
Explanation:
(5+7+2) − (6+8+8) = 14 − 22 = -8
For 56782: (5+7+2) =14, (6+8)=14
⇒ Difference = 0
Shortcut Trick: Sum of alternate digits must differ by 0 or a multiple of 11.
2. What is the remainder when 987654 is divided by 9?
A. 2 B. 3
C. 4 D. 6
Correct Answer: D
Explanation:
Sum of digits = 9+8+7+6+5+4 = 39
39 ÷ 9 leaves a remainder of 3.
Since 987654 = 9×109739 + 3
3. How many prime numbers lie between 20 and 40?
A. 4 B. 5
C. 6 D. 7
Correct Answer: A
Explanation:
Primes: 23, 29, 31, 37
Total = 4
4. The HCF of 72 and 120 is:
A. 12 B. 24
C. 36 D. 48
Correct Answer: B
Explanation:
72 = 2³ × 3²
120 = 2³ × 3 × 5
HCF = 2³ × 3 = 24
Shortcut Trick: Take common factors with minimum powers.
5. The LCM of 18 and 24 is:
A. 48 B. 60
C. 72 D. 96
Correct Answer: C
Explanation:
18 = 2 × 3²
24 = 2³ × 3
LCM = 2³ × 3² = 72
6. Which of the following is a perfect square?
A. 784 B. 786
C. 788 D. 790
Correct Answer: A
Explanation:
28² = 784
Shortcut Trick: Last digit 4 and square root 28.
7. What is the unit digit of 7⁵³?
A. 1 B. 3
C. 7 D. 9
Correct Answer: C
Explanation:
Cycle of 7: 7,9,3,1
53 ÷ 4 leaves a remainder 1
Unit digit = 7
Actually remainder = 1
⇒ answer should be 7.
8. Find the number of factors of 360.
A. 20 B. 24
C. 28 D. 30
Correct Answer: B
Explanation:
360 = 2³ × 3² × 5¹
Factors = (3+1)(2+1)(1+1)
= 4×3×2
= 24
9. Which number is divisible by 3?
A. 84571 B. 91284
C. 65321 D. 74210
Correct Answer: B
Explanation:
9+1+2+8+4 = 24
24 is divisible by 3.
10. The smallest prime number is:
A. 0 B. 1
C. 2 D. 3
Correct Answer: C
Explanation:
2 is the only even prime number.
11. What is the remainder when 2¹⁰ is divided by 7?
A. 1 B. 2
C. 3 D. 4
Correct Answer: B
Explanation:
2³ = 8 ≡1 (mod 7)
2¹⁰ = (2³)³ × 2
= 1×2
= 2
12. The product of two co-prime numbers is 221. One number is 13. The other is:
A. 15 B. 16
C. 17 D. 19
Correct Answer: C
Explanation:
221 ÷ 13 = 17
13. Which of the following is not a prime number?
A. 29 B. 31
C. 39 D. 41
Correct Answer: C
Explanation:
39 = 3 × 13
14. What is the square root of 1764?
A. 40 B. 41
C. 42 D. 44
Correct Answer: C
Explanation:
42² = 1764
15. If HCF = 12 and LCM = 720 of two numbers, and one number is 144, the other number is:
A. 48 B. 60
C. 72 D. 80
Correct Answer: B
Explanation:
Product of numbers = HCF × LCM
= 12 × 720 = 8640
Other number = 8640 ÷ 144 = 60
Shortcut Trick: a × b = HCF × LCM
SSC CGL Number System MCQs
16. The cube root of 2197 is:
A. 11 B. 12
C. 13 D. 14
Correct Answer: C
Explanation:
13³ = 2197
17. Find the least number divisible by 2, 3, 4, 5 and 6.
A. 30 B. 60
C. 90 D. 120
Correct Answer: B
Explanation:
LCM(2,3,4,5,6)=60
18. Which of the following numbers is divisible by 8?
A. 3452 B. 5466
C. 7822 D. 9126
Correct Answer: A
Explanation:
Last three digits = 452
452 ÷ 8 = 56.5
Actually, 3456 would work, not 3452.
Checking all:
3452 ÷ 8 = 431.5
5466 ÷ 8
7822 ÷ 8
9126 ÷ 8
(No correct option)
SSC-style corrected answer: 3456 would be divisible by 8.
SSC CGL Number System MCQs
19. The sum of the first 20 natural numbers is:
A. 190 B. 200
C. 210 D. 220
Correct Answer: C
Explanation:
n(n+1)/2
20×21/2 = 210
20. How many zeros are there at the end of 50!?
A. 10 B. 12
C. 14 D. 15
Correct Answer: B
Explanation:
50/5 =10
50/25 =2
Total =12
Shortcut Trick: Count powers of 5.
21. The greatest 4-digit number divisible by 15 is:
A. 9975 B. 9990
C. 9995 D. 9980
Correct Answer: A
Explanation:
9999 ÷15 = 666 remainder 9
9999 − 9 = 9990
9990 divisible by 15.
Correct Answer: B
22. What is the unit digit of 3⁴⁵?
A. 1 B. 3
C. 7 D. 9
Correct Answer: C
Explanation:
Cycle: 3,9,7,1
45 mod 4 =1
Unit digit = 3
Correct Answer: B
SSC CGL Number System MCQs
23. Which number leaves a remainder 1 when divided by 2,3,4,5,6?
A. 59 B. 60
C. 61 D. 62
Correct Answer: C
Explanation:
LCM(2,3,4,5,6) = 60
Required number = 60 + 1 =61
.
24. Find the HCF of 84, 126 and 210.
A. 21 B. 28
C. 42 D. 14
Correct Answer: A
Explanation:
Common highest factor = 21
25. The number of prime factors of 180 is:
A. 2 B. 3
C. 4 D. 5
Correct Answer: B
Explanation:
180 = 2² × 3² × 5
Prime factors = 2,3,5
Total = 3
26. Which is the smallest perfect square divisible by 18?
A. 18 B. 36
C. 72 D. 144
Correct Answer: B
Explanation:
18 = 2 × 3²
Multiply by 2 ⇒ 36
27. The value of (999² − 1)/998 is:
A. 999 B. 1000
C. 998 D. 1001
Correct Answer: B
Explanation:
999²−1=(999−1)(999+1)
=998×1000
÷998=1000
Shortcut Trick: a²−b²=(a−b)(a+b)
28. The least prime number greater than 50 is:
A. 51 B. 53
C. 55 D. 57
Correct Answer: B
Explanation:
53 is prime.
29. What is the remainder when 12345 is divided by 11?
A. 1 B. 2
C. 3 D. 4
Correct Answer: C
Explanation:
(1 + 3 + 5) − (2 + 4)
=9 − 6 =3
30. The smallest number which, when divided by 12 and 18, leaves a remainder of 5 is:
A. 36 B. 41
C. 77 D. 113
Correct Answer: B
Explanation:
LCM(12,18)=36
Required number = 36+5
=41
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