RRB NTPC Number System Questions, Check Solved Problems With Solution

The RRB NTPC exam is one of the most competitive railway recruitment examinations in India, with lakhs of students appearing each year. Among the various topics asked in the Mathematics section, the Number System is one of the most fundamental yet highly scoring areas. Understanding concepts like divisibility, LCM & HCF, fractions, decimals, indices, and rational/irrational numbers is crucial for clearing the cut-off. In this article, we will provide a complete and easy-to-understand guide on RRB NTPC Number System Questions, including important concepts, formulas, sample questions, difficulty levels, and preparation tips.

Download RRB NTPC Number System Questions PDF

Candidates can download the RRB NTPC Number System Questions PDF to practice important questions on divisibility, LCM, HCF, remainders, factors, multiples, and other commonly tested number system concepts. The PDF is useful for quick revision and regular practice for the RRB NTPC exam. Candidates can solve the questions first and then check the answers to analyze their accuracy.

Download RRB NTPC Number System Questions PDF

What are the types of RRB NTPC Number System Questions?

There are various types of number system questions asked from topics like divisibility rules, LCM and HCF, BODMAS, and more. The RRB NTPC Notification 2026 will be released for the applicants. The number system questions generally come from the following subtopics:

• Types of numbers (Natural, Whole, Integer, Rational, Irrational, Real)
• Divisibility rules
• LCM and HCF
• Fractions and decimals
• Square and cube roots
• BODMAS application
• Indices and surds
• Remainders (Basic level)
• Factorization

Topic-wise weightage of Number System Questions in RRB NTPC

Candidates must understand the difficulty level of each of the mathematics topics asked in the examination. The expected distribution of questions based on past trends is shown below:

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Sample RRB NTPC Number System Questions

In the CBT 1 examination, there are in total of 30 questions from Mathematics. On the other hand, qualifying candidates are required to answer 35 questions from the CBT 2 exam. We have provided below a set of RRB NTPC Number System Questions that will help candidates get an idea about the difficulty level:

Q1. What is the largest 4-digit number exactly divisible by 5, 12, and 22?
(a) 9900
(b) 8580
(c) 9240
(d) 10560
Answer: (a) 9900

Q2. What is the largest 4-digit number exactly divisible by 8, 14, and 21?
(a) 9912
(b) 9576
(c) 9744
(d) 10080
Answer: (a) 9912

Q3. What is the largest 4-digit number exactly divisible by 4, 6, and 10?
(a) 9840
(b) 9960
(c) 9900
(d) 10020
Answer: (b) 9960

Q4. What is the largest 4-digit number exactly divisible by 9, 12, and 18?
(a) 9900
(b) 9936
(c) 10008
(d) 9972
Answer: (d) 9972

Q5. What is the largest 4-digit number exactly divisible by 16, 20, and 24?
(a) 9360
(b) 9600
(c) 10080
(d) 9840
Answer: (d) 9840

Q6. What is the largest 4-digit number exactly divisible by 6, 20, and 28?
(a) 8820
(b) 9660
(c) 9240
(d) 10080
Answer: (b) 9660

Q7. What is the largest 4-digit number exactly divisible by 2, 13, and 27?
(a) 8424
(b) 9126
(c) 9828
(d) 10530
Answer: (c) 9828

Q8. What is the largest 4-digit number exactly divisible by 3, 13, and 30?
(a) 8970
(b) 9360
(c) 10140
(d) 9750
Answer: (d) 9750

Q9. What is the smallest 4-digit number exactly divisible by 18?
(a) 1008
(b) 972
(c) 990
(d) 1026
Answer: (a) 1008

Q10. What is the smallest 4-digit number exactly divisible by 24?
(a) 1008
(b) 960
(c) 984
(d) 1032
Answer: (a) 1008

Q11. What is the smallest 4-digit number exactly divisible by 28?
(a) 952
(b) 1008
(c) 980
(d) 1036
Answer: (b) 1008

Q12. What is the smallest 4-digit number exactly divisible by 36?
(a) 936
(b) 972
(c) 1008
(d) 1044
Answer: (c) 1008

Q13. What is the least number that must be added to 6785 to make the result exactly divisible by 9?
(a) 1
(b) 2
(c) 3
(d) 4
Answer: (a) 1

Q14. What is the least number that must be added to 5432 to make the result exactly divisible by 11?
(a) 3
(b) 4
(c) 2
(d) 5
Answer: (c) 2

Q15. What is the least number that must be subtracted from 9876 to make the result exactly divisible by 13?
(a) 9
(b) 10
(c) 11
(d) 12
Answer: (a) 9

Key Points - RRB NTPC Number System Questions

The key points of the article are summarised below. Check them out:

• Understand rules for 2, 3, 4, 5, 6, 8, 9, 10, 11, and 12.
• Essential for LCM, HCF, and factor-related questions.
• Use prime factorisation or Euclid's method.
• Key for solving problems on sharing, distribution, and ratios.
• Use prime factorisation or formula: LCM × HCF = Product of numbers.
• Frequently appears in time and work, train problems, and pattern questions.
• Natural, Whole, Integers, Rational, Irrational, Prime, Composite.
• Important for categorising numbers and applying correct properties.
• Even/Odd, Prime/Composite, Perfect Squares/Cubes.
• Knowledge of these properties helps in simplification and reasoning.
• Use the cyclicity of unit digits for powers.
• Apply modular arithmetic for remainder-related questions.
• Fraction ↔ Decimal, Decimal ↔ Percentage, Ratio ↔ Fraction.
• Critical for solving ratio, proportion, and percentage-based number problems.
• Identify arithmetic or geometric progressions.
• Common in questions involving sequences, missing numbers, and sums.
• Memorise small prime numbers, squares, cubes, and divisibility shortcuts.
• Practice mental calculations for faster problem-solving.
• Solve topic-wise questions: HCF/LCM, Divisibility, Unit Digit, Remainder.
• Gradually move to mixed sets to improve speed and accuracy.

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