Number Series is an important topic in the Numerical Ability section of IBPS RRB Clerk exam. These questions are one of the easiest and most scoring in the exam. These questions test your ability to identify patterns and apply logic quickly. Whether you’re preparing for Prelims or Mains, number series questions can help you gain 5 marks in just a few minutes. With regular practice, you can solve them in under 30 seconds. In this blog, we’ll explain the most asked types of number series questions, give solved examples, and share tips to help you master this topic. You can also download a free PDF of sample number series questions in IBPS RRB Clerk exam for practice.
Download PDF – Practice Sample Number Series Questions
To help you prepare better, we’ve created a free PDF with the most frequently asked number series questions in IBPS RRB Clerk exams. It includes all types of number series asked in the exam, with answers and explanations. In this PDF, we have included the 15 questions asked in the previous year on this topic. You can use it for daily revision or mock test practice. Download it now and start solving!
Click Here to Download Sample Number Series Questions PDF!
Why Number Series is Important for IBPS RRB Clerk Exam?
Number series questions appear regularly in the Quant section of the IBPS RRB Clerk exam. In Prelims, you may get 5 questions from this topic, and in Mains, the level may be slightly higher. These questions are quick to solve and don’t require long calculations. If you understand the pattern, you can solve them in seconds. That’s why this topic is a favourite among students. It helps you save time and boost your score. Practicing number series daily improves your speed, accuracy, and confidence in the exam.
Types of Number Series Questions Asked in IBPS RRB Clerk
Let’s look at the most common types of number series questions you’ll see in the exam. Each type has a different logic, and once you understand the pattern, solving becomes easy.
1. Arithmetic Series (Addition/Subtraction)
These series follow a fixed addition or subtraction pattern.
Example:
2, 5, 8, 11, 14, ?
Logic: Add 3 each time.
Answer: 17
These are the simplest types. Just check the difference between numbers. If it’s constant, it’s an arithmetic series.
2. Multiplication or Division Series
Here, each number is multiplied or divided by a fixed number.
Example:
2, 4, 8, 16, 32, ?
Logic: Multiply by 2
Answer: 64
These series grow fast. Look at how the numbers increase or decrease. If the change is big, try multiplication or division.
3. Mixed Operations (Add + Multiply)
These series use a mix of operations like adding and multiplying.
Example:
2, 5, 10, 17, 26, ?
Logic: Add 3, 5, 7, 9…
Answer: 37
Here, the difference between numbers increases in a pattern. Check how the gap changes and apply the logic.
4. Square or Cube Series
These series are based on squares or cubes of numbers.
Example:
1, 4, 9, 16, 25, ?
Logic: Squares of 1, 2, 3, 4, 5…
Answer: 36
If the numbers look familiar, try checking if they are squares or cubes. These are easy to spot with practice.
5. Alternating Series
In these series, two patterns run in alternate positions.
Example:
2, 4, 6, 10, 12, 14, ?
Logic: Two series: Even numbers and +4 pattern
Answer: 18
Check if every second number follows a different rule. These are tricky but easy once you spot the pattern.
6. Wrong Number Series
Here, one number in the series is wrong. You have to find it.
Example:
3, 6, 12, 24, 50, 96
Logic: Multiply by 2 → 3×2=6, 6×2=12, 12×2=24, 24×2=48 (not 50)
Answer: 50 is wrong
These questions test your observation. Look for the number that breaks the pattern. Solve more wrong number series questions. Know more about wrong number series from here!
7. Odd One Out Series
Odd one out questions are a special type of number series where one number doesn’t follow the pattern.
Solved Example
Question:
3, 6, 12, 24, 50, 96
Step-by-Step Logic:
- 3×2 = 6
- 6×2 = 12
- 12×2 = 24
- 24×2 = 48 (but here it’s 50, which is wrong)
- 48×2 = 96
Answer: 50 is the odd one out.
This number breaks the pattern of multiplying by 2. So it’s the incorrect number in the series.
Some Solved Examples for Your Reference
Below, we have provided 5 solved examples which is most relevant for your upcoming IBPS RRB Clerk exam. First, try to solve it yourself without lifting a pen or paper, then see the solution.
1. Series: 7, 14, 29, 58, 117, ?
Step-by-Step Logic:
- Look at the pattern: each term is roughly double the previous, but slightly adjusted.
- 7 × 2 = 14
- 14 × 2 + 1 = 29
- 29 × 2 = 58
- 58 × 2 + 1 = 117
- Next: 117 × 2 = 234
Answer: 234
Tip: When numbers grow quickly but not exactly double, check for alternating “×2” and “×2 + 1” patterns.
2. Series: 3, 9, 21, 45, 93, ?
Step-by-Step Logic:
- Differences: 9–3 = 6, 21–9 = 12, 45–21 = 24, 93–45 = 48.
- Differences are doubling each time: 6, 12, 24, 48… next is 96.
- Add 96 to 93 → 189
Answer: 189
Tip: If multiplication doesn’t fit, check the differences. Many advanced series use differences that grow in a pattern.
3. Series: 2, 6, 18, 54, 162, ?
Step-by-Step Logic:
- Each term is multiplied by 3.
- 2 × 3 = 6
- 6 × 3 = 18
- 18 × 3 = 54
- 54 × 3 = 162
- Next: 162 × 3 = 486
Answer: 486
Tip: Multiplication-based series often appear in Prelims. In harder sets, they may combine multiplication with addition.
4. Series: 5, 12, 26, 54, 110, ?
Step-by-Step Logic:
- Differences: 12–5 = 7, 26–12 = 14, 54–26 = 28, 110–54 = 56.
- Differences are doubling: 7, 14, 28, 56… next is 112.
- Add 112 to 110 → 222
Answer: 222
Tip: Always check if the differences themselves form a series (like doubling, squares, or multiples).
5. Series: 1, 4, 13, 40, 121, ?
Step-by-Step Logic:
- Look for multiplication + addition.
- 1 × 3 + 1 = 4
- 4 × 3 + 1 = 13
- 13 × 3 + 1 = 40
- 40 × 3 + 1 = 121
- Next: 121 × 3 + 1 = 364
Answer: 364
Difference Between Missing Number Series and Wrong Number Series
Check the difference between the missing and wrong number series.
| Feature | Missing Number Series | Wrong Number Series |
| Definition | A number is missing in the series; you need to find it. | One number is incorrect in the series; you need to spot it. |
| Objective | Identify the correct number that completes the pattern. | Identify the number that breaks the pattern. |
| Pattern | All numbers follow a logical pattern except the blank. | All numbers follow a pattern except the wrong one. |
| Question Format | Usually shown as: 2, 4, __, 8, 10 | Usually shown as: 2, 4, 9, 8, 10 |
| Approach | Find the logic and apply it to fill the blank. | Find the logic and check which number doesn’t fit. |
| Answer Type | A number that completes the series. | A number that should be removed or replaced. |
| Common in Exams | Frequently asked in Prelims and Mains. | Often seen in Mains or higher-level reasoning sets. |
| Difficulty Level | Usually easier and quicker to solve. | Slightly tricky; needs careful observation. |
Conclusion
Number series questions are a scoring opportunity in the IBPS RRB Clerk exam. They are short, logical, and easy to solve once you understand the common patterns like addition, multiplication, squares, and alternating sequences. With regular practice and smart observation, you can solve most of these questions in under 30 seconds. The more you solve, the faster and more confident you’ll become in the exam. Keep practicing and stay consistent!
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Related Blogs:
| IBPS RRB Clerk Cut Off 2025 | IBPS RRB Clerk Syllabus 2025 |
| IBPS RRB Clerk Salary 2025 | IBPS RRB Clerk Previous Year Paper |
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FAQs
Generally, 5 questions are asked in the Prelims exam.
Yes. These questions are asked in Mains exam too, with a slightly higher difficulty level.
Start by checking the difference between numbers. If the change is big, try multiplication. Look for patterns like squares, cubes, or alternating logic. With practice, you’ll spot the rule in seconds.
Yes! With regular practice and understanding of patterns, you can solve most number series questions in 20–30 seconds. Use a timer while practicing to improve speed.
Disclaimer: This article has been prepared for informational and educational purposes only, based on previous exam trends, expert analysis, and publicly available data. It is not an official notification, and the Institute of Banking Personnel Selection (IBPS) — the official conducting authority for the RRB Clerk exam — has not endorsed or released the content herein. While every effort has been made to ensure accuracy, exam patterns and question types may change, and readers are advised to verify details with official IBPS updates. The practice material and predictions provided are intended to support preparation and should not be considered guaranteed exam content. Neither the authors nor PracticeMock accept responsibility for any discrepancies, errors, or outcomes arising from reliance on this article. For official information, please refer to the IBPS website.
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