What is the sum of the first 18 natural numbers?

171 — Sum = n(n+1)/2 = 18 × 19/2 = 171.

What is the remainder when 157 is divided by 12?

1 — 12 × 13 = 156, and 157 − 156 = 1, so the remainder is 1.

What is the smallest 4-digit number exactly divisible by 12?

1008 — The smallest 4-digit number is 1000. Dividing 1000 by 12 gives a remainder of 4, so the next multiple of 12 is 1000 + (12 − 4) = 1008.

Find the least common multiple of 8, 12 and 16.

48 — The smallest number divisible by 8, 12, and 16 is 48.

What is the square root of 3,969?

63 — 63 × 63 = 3,969, so the square root of 3,969 is 63.

Which of the following is a prime number: 33, 39, 41, 45?

41 — 41 has no factors other than 1 and itself, so it is prime. 33 (3×11), 39 (3×13), and 45 (9×5) are all composite.

Quantitative practice

Number System Questions with Answers

Divisibility, factors, remainders, HCF and LCM, and the unit-digit and last-two-digit shortcuts. This page pools every number system question on the site — 142 of them, from 37 exams, weighted towards Management, Banking, Railways — so you can drill the topic on its own instead of meeting four of them inside a full paper.

5% of the pool is graded hard on this site’s own scale and 42% easy, which is gentler than the average topic in this section.

Questions: 142
Practice set: 25 in 25 min
Difficulty: 60/75/7
Negative marking: None

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Number System questions with solutions

6 from the 142-question pool, worked in full.

1. What is the sum of the first 18 natural numbers?
- A. 161
- B. 171 ✓
- C. 167
- D. 175
Solution. Sum = n(n+1)/2 = 18 × 19/2 = 171.
2. What is the remainder when 157 is divided by 12?
- A. 1 ✓
- B. 3
- C. 5
- D. 7
Solution. 12 × 13 = 156, and 157 − 156 = 1, so the remainder is 1.
3. What is the smallest 4-digit number exactly divisible by 12?
- A. 1000
- B. 1002
- C. 1012
- D. 1008 ✓
Solution. The smallest 4-digit number is 1000. Dividing 1000 by 12 gives a remainder of 4, so the next multiple of 12 is 1000 + (12 − 4) = 1008.
4. Find the least common multiple of 8, 12 and 16.
- A. 36
- B. 44
- C. 48 ✓
- D. 52
Solution. The smallest number divisible by 8, 12, and 16 is 48.
5. What is the square root of 3,969?
- A. 61
- B. 65
- C. 63 ✓
- D. 67
Solution. 63 × 63 = 3,969, so the square root of 3,969 is 63.
6. Which of the following is a prime number: 33, 39, 41, 45?
- A. 33
- B. 41 ✓
- C. 39
- D. 45
Solution. 41 has no factors other than 1 and itself, so it is prime. 33 (3×11), 39 (3×13), and 45 (9×5) are all composite.

Exams that set Number System

7 categories, led by Management, Banking, Railways.

Also set by MICAT, NABARD Grade A, Navy SSR, NMAT, RBI Assistant, RBI Grade B, RPF Constable, RPF Sub-Inspector, RRB ALP, RRB Group D, RRB Junior Engineer, RRB NTPC, RRB Technician, SBI Clerk, SBI PO, SEBI Grade A, SIDBI Grade A & B, SNAP, SSC CGL, SSC CHSL, SSC CPO, SSC GD Constable, SSC Selection Post, TANCET MBA, UPSC CSE. Browse all exams.

Number System: frequently asked questions

How many number system questions are there?

142, from the 37 exams here whose syllabus sets the topic. 42% are graded easy and 5% hard, which makes number system one of the more tractable topics in this section, against a 17% average.

Which exams ask number system questions?

37 of the exams on this site, weighted towards Management (11), Banking (10), Railways (7). Every question in this pool comes from one of their own mock tests, so the list below is the honest answer to whether the topic is worth your time.

Is number system hard?

5% of these 142 questions are graded hard and 42% easy, making it one of the more tractable topics in this section, against a 17% average.

Number System Questions with Answers

Number System questions with solutions

Exams that set Number System

Number System: frequently asked questions

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