**Number Series questions** are an important part of **competitive exams**, especially in the **logical reasoning section**. These questions present a series of numbers with a missing value that you need to fill in by identifying the already existing pattern. In the start, it may seem straightforward, but understanding the logic behind the pattern can be quite challenging. In this article, we will explore different types of number series, provide instructions on how to approach them, and offer 40 sample questions with solutions to help you ace these problems.

Table of Contents

## Types of Number Series Questions

Here we have categorized number series questions into the following types:

**Series with Increasing Difference:**This is the most common type, where the difference between consecutive numbers consistently increases.**Series with Constant Difference:**In this type, the difference between each pair of successive numbers remains the same.**Series with Decreasing Difference:**Here, the difference between consecutive numbers decreases as you move along the series.**Perfect Squares and Cubes Series:**These series involve the squares or cubes of numbers, either directly or indirectly.**Miscellaneous Series:**This category includes series that may have various operations like addition, subtraction, multiplication, or division.

**Also Read: Number Series Questions for Competitive Exams**

## Instructions to Solve Number Series Logical Reasoning Questions

To tackle number series questions effectively, you can employ several strategies:

- Start by examining the differences between consecutive numbers. If you notice a consistent difference, it likely falls under the “constant difference” category.
- If the differences themselves are increasing or decreasing, the series may belong to the “increasing difference” or “decreasing difference” category, respectively.
- If differences don’t provide a clear answer, try dividing one number by the previous one. If the result is consistent, it might be a “product series.”
- Express each term as a product of two factors and search for patterns among these factors.

## Questions on Number Series Logical Reasoning With Detailed Explanations

**Q1. Find the missing term: 2, 5, 12.5, ? 78.125, 195.3125**

**Answer:** (a) 31.25**Explanation:** Each term is obtained by multiplying the previous term by 2.5.

**Q2. Find the missing term: 50, 45, 40, 35, 30,?**

**Answer:** (c) 25**Explanation: **This is a constant difference series with a difference of -5.

**Q3. Find the missing term: -10, -8, 6, 40, 102,?**

**Answer**: (b) 117**Explanation: **This is a square series based on consecutive odd numbers.

**Q4. Find the missing term: 25, 49, 121, 169,?**

**Answer**: (c) 289**Explanation**: This series combines perfect squares with prime numbers.

**Q5. Find the missing terms in the series: 1, 30, 5, 26, 9, 22, 13, 18, ?,?**

**Answer**: (a) 17, (b) 22**Explanation**: This series is a combination of two different sequences: +4 and +5.

**Q6. Find the missing term in the series: 4, 18, ? 100, 180, 294, 448.**

**Answer**: (d) 48**Explanation**: This is a square and cube series with an addition of 2.

**Q7. Find the missing term: 11, 12, 15, 20, 27,?**

**Answer**: (a) 36**Explanation**: The series follows a pattern of summing consecutive odd numbers.

**Q8. Find the missing term: 14, 25, 47, 91, 179,?**

**Answer**: (c) 355**Explanation**: The difference between consecutive terms doubles with each step.

**Q9. Find the missing term: 4, 6, 9, 14, 21,?**

**Answer**: (b) 32**Explanation**: The difference between consecutive terms is a prime number.

**Q10. Find the missing terms in the series: 3, 4, 7, 8, 11, 12, ?,?**

**Answer**: (a) 13, 14**Explanation**: This is a combination of a difference of 2 and a difference of squares.

**Q11. Identify the wrong number in the series: 2, 3, 12, 37, 86, 166, 288.**

**Answer**: (d) 166**Explanation**: Each term is formed by adding the previous term and consecutive odd-number squares, except for 166.

**Q12. Find the missing term: 81: 101:: 121:?**

**Answer**: (d) 145**Explanation**: This series involves square and prime number patterns.

**Q13. Find the missing term: 11: 121:: 15:?**

**Answer**: (c) 225**Explanation**: This series consists of squares of numbers.

**Q14. Find the missing term: 2, 4, 8, 10, 14,?**

Answer: (a) 16

Explanation: This is an alternating series with a pattern of +2 and +4.

**Q15. Find the missing term: 1, 8, 9, 64,?**

**Answer**: (c) 25**Explanation**: This series alternates between squares and cubes.

**Q16. Find the missing term: 6, 11, 18, 27,?**

**Answer**: (c) 38**Explanation**: This series involves squares with an addition of 2.

**Q17. Find the missing term: 3, 3, 4.5, 9,?**

**Answer**: (a) 22.5**Explanation**: This is a product-based series with each term multiplied by a certain value.

**Q18. Find the missing terms: 3, 5, 7, 9, 11,?**

**Answer**: (a) 13**Explanation**: This is both a difference of 2 and a difference of squares.

**Q19. Find the missing term: 1, 7, 37, 187, 937,?**

**Answer**: (a) 4687**Explanation**: Each term is obtained by multiplying the previous term by 5 and adding 2.

**Q20. Find the missing term: 1, 5, 19, 81,?**

Answer: (b) 411

Explanation: This series involves multiplication and addition in an increasing pattern.

## Missing Terms Logical Reasoning Questions in the Series Section

Missing terms category is an important category under series section in logical reasoning.Here are some questions for practice:

**Q1. Find the missing term: 2, 5, 12.5,? 78.125, 195.3125**

Answer: 31.25

**Q2. Find the missing term: 50, 45, 40, 35, 30,? **

Answer:25

**Q3. Find the missing term: -10, -8, 6, 40, 102,?**

Answer:117

**Q4. Find the missing term: 25, 49, 121, 169,?**

Answer:289

**Q5. Find the missing term: 1, 30, 5, 26, 9, 22, 13, 18,?**Answer:17

**Q6. Find the missing term: 4, 18,? 100, 180, 294, 448.**

Answer:48

**Q7. Find the missing term: 11,12,15,20,27,? **

Answer:36

**Q8. Find the missing term: 14, 25, 47, 91, 179, ?.**

Answer:55

**Q9. Find the missing term: 4, 6, 9, 14, 21, ?.**

Answer:32

**Q10. Find the missing terms: 3, 4, 7, 8, 11, 12, ??. **

Answer:15,16

**Q11. Find the wrong number: 2, 3, 12, 37, 86, 166, 288.**

Answer:166

**Q12. Find the missing term: 81: 101:: 121:?**

Answer:145

**Q13. Find the missing term: 11 : 121:: 15:?**

Answer:225

**Q14. Find the missing term: 2, 4, 8, 10, 14, ?.**

Answer:116

**Q15. Find the missing term: 1, 8, 9, 64, ?. **

Answer:25

**Q16. Find the missing term: 6, 11, 18, 27, ?. **

Answer:38

**Q17. Find the missing term: 3, 3, 4.5, 9, ?.**

Answer:22

**Q18. Find the missing term: 3, 5, 7, 9, 11, ?.**

Answer:13

**Q19. Find the missing term: 1, 7, 37, 187, 937, ?.**

Answer:4687

**Q20. Find the missing term: 1, 5, 19, 81, ?**

Answer:411

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