Number series questions are a staple in the Quantitative Aptitude section of RRB PO (Prelims). They examine your ability to spot patterns, apply arithmetic operations, and reason under time pressure. In recent years, 5–6 questions from the number series have appeared in the prelims. So mastering this topic can give you a reliable scoring edge in the competition. In this blog, we are providing the RRB PO Number series questions PDF. Use this PDF to practice this concept well before the examination.
Download the RRB PO Number Series Question PDF
In this section, we are providing RRB PO Number series questions PDF. Practice questions from this PDF and make yourself exam-ready.
Download the RRB PO Number Series Question PDF
Types of Number Series
These patterns regularly appear in RRB PO exams as per the analysis of previous year papers by our experts:
| Type | Description | Example Pattern |
| Addition / Subtraction | Each term is obtained by adding/subtracting a value (may change) | 5, 8, 13, 22, 37 (add increasing differences) |
| Multiplication / Division | Terms multiply or divide by a fixed (or varying) factor | 2, 4, 12, 48 (×2, ×3, ×4…) |
| Mixed Operation | Combination of +, –, ×, ÷ within a series | 3, 6, 20, 63, … |
| Square / Cube / Powers | Terms come from squares, cubes, or powers | 1, 4, 9, 16, 25 |
| Alternate Patterns | Two or more interleaved sequences | 2, 9, 4, 16, 6, 25 … (even positions are squares) |
| Difference Series | Differences between terms form a recognisable pattern | 13, 18, 25, 34… (differences: 5, 7, 9…) |
| Wrong / Odd One Out | One number doesn’t fit the pattern | 2, 4, 8, 14, 16 → 14 is odd |
| Geometric Progression (GP) | Multiplication by a constant factor | 3, 9, 27, 81 |
Understanding these types helps you categorise a question quickly.
Strategy to Master Number Series
Follow these steps to optimise your learning and performance:
- Understand the logic first
Before solving many questions, spend time with smaller series and see how patterns evolve. - Start with the easier ones
In an exam, kick off with simpler arithmetic or square/cube sequences. Leave complex ones for later. - Time yourself
Aim to solve a series in ≤ 60 seconds in practice. In the exam, allot 5–6 minutes total for the number series portion. - Use the PDF smartly
- Attempt batches of 10 under timed conditions.
- After solving, inspect the wrong answers in depth.
- Identify which pattern you mistook.
- Attempt batches of 10 under timed conditions.
- Simulate real exams
In full mocks, force yourself to attempt number series in the allotted time as if it’s the final exam. - Classify your mistakes
Maintain an error log where you note down:
- The pattern type
- Your mistake (misread, wrong logic, arithmetic error)
- How to avoid it next time
- The pattern type
- Regular revision
Go back to tricky types (alternate, mixed) regularly. Over time, you’ll see “new” series are often just combinations of known ones.
Sample Questions & Explanation
Here are 4 sample number series questions (from past trends) with reasoning:
- 28, ?, 48, 73, 108, 153
- You need to find the missing term.
- Differences: ? → 48 = +?, 48 → 73 = +25, 73 → 108 = +35, 108 → 153 = +45
- Pattern in differences: +15, +25, +35, +45 (i.e. +10 increase each time)
- So missing difference before 25 would be +15 → 28 + 15 = 43
- You need to find the missing term.
- 16, 33, 68, 139, 282, ?
- Observe ratio/increment patterns
- Each term approx double + a constant
- 16 × 2 = 32 → +1 = 33
- 33 × 2 = 66 → +2 = 68
- 68 × 2 = 136 → +3 = 139
- 139 × 2 = 278 → +4 = 282
- Next: 282 × 2 = 564 → +5 = 569
- Observe ratio/increment patterns
- 228, 227, 223, 214, ?, 173
- Differences: –1, –4, –9, …
- These are squares: 1, 4, 9, 16 …
- So next difference = –16 → 214 – 16 = 198
- Differences: –1, –4, –9, …
- 66, 78, ?, 82, 74, 86
- Alternate pattern: positions 1, 3, 5 might follow one logic; 2, 4, 6 another
- Positions 2, 4, 6: 78 → 82 → 86 (add +4)
- So odd positions: 66 →? → 74 follow +4 as well → 66 → 70 → 74
- Hence? = 70
- Alternate pattern: positions 1, 3, 5 might follow one logic; 2, 4, 6 another
Tips to Score All Questions in the Exam
- Don’t overcomplicate — most number series are based on simple operations.
- Skip very time-consuming ones — never waste more than 90 seconds on one.
- Use pencil & paper smartly — write differences/ratios in columns.
- Watch out for trick options — sometimes two or more seem plausible; test them forward.
- Keep calm — mistakes usually come under pressure. A cool approach helps.
Conclusion
In this article, we are providing number series questions for RRB PO Exam 2025. To practice more such reasoning questions, you can take the subscription to our test series. In this test series, you will get a simulation of the exam environment along with a detailed analysis of the mock test.
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IBPS RRB PO 2025 Related Link
| IBPS RRB PO Salary | IBPS RRB PO Exam Pattern |
| IBPS RRB PO Cut Off | IBPS RRB PO Previous Year Question Papers |

FAQs
Usually, 5–6 questions appear in the prelims exam, making it one of the easiest scoring topics in Quantitative Aptitude.
You can expect missing numbers, wrong numbers, and pattern-based questions, involving arithmetic, geometric, or mixed operations.
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