In the IBPS Clerk 2025 exam, Wrong Number Series is one of those topics that most candidates find tougher compared to Missing Number Series. The reason is simple: in a missing number series, you just need to find the next number, but in a wrong number series, you have to carefully spot the odd number that breaks the logic. This makes the question a bit confusing and time-consuming during the exam. So here we are providing the IBPS Clerk wrong number series full concept, along with the most asked questions and their solutions.
What are Wrong Number Series Questions?
A Wrong Number Series is a type of numerical puzzle where a sequence of numbers is given, and one number does not fit the pattern. The candidate’s task is to identify the wrong number that breaks the logic of the series.
For example:
3, 6, 12, 24, 50, 96, 192
Here, the logic is ×2 each time. The wrong number is 50, because instead of 48, 50 is placed.

Why are wrong number series questions important in IBPS Clerk 2025?
In IBPS Clerk 2025 prelims, you can expect 3-5 questions from wrong number series, while in mains, 4-6 questions may come in the quantitative aptitude section.
- High frequency in exams: These questions are asked regularly in both prelims and mains.
- Time saving: If the logic is understood quickly, it takes less than 30 seconds to solve each question.
Types of Wrong Number Series Questions
- Arithmetic Progression (AP) Based
- The series follows a pattern of addition or subtraction.
- Example: 5, 10, 15, 22, 25, 30 → Wrong number = 22 (should be 20).
- Geometric Progression (GP) Based
- The series follows multiplication or division rules.
- Example: 2, 4, 8, 16, 34, 64 → Wrong number = 34 (should be 32).
- Square/Cube Pattern
- Based on perfect squares or cubes with some adjustments.
- Example: 1, 4, 9, 16, 25, 49, 36 → Wrong number = 49 (should be 36 after 25).
- Prime Number Series
- Based on prime numbers in increasing/decreasing order.
- Example: 2, 3, 5, 7, 11, 14, 17 → Wrong number = 14 (should be 13).
- Mixed Pattern Series
- A combination of addition, subtraction, multiplication, division, or squares.
- Example: 3, 6, 12, 24, 49, 96 → Wrong number = 49 (should be 48).
Most Asked Wrong Number Series Questions PDF link
Question 1: What will come in place of the question mark (?) in the following series?
21, 141, 201, 241, 271, ?
A) 297
B) 295
C) 293
D) 291
E) 289
Question 2: What will come in place of the question mark (?) in the following series?
41, 42, ?, 76, 125, 206
A) 46
B) 49
C) 51
D) 54
E) 56
Question 3: What will come in place of the question mark (?) in the following series?
77, 84, 105, 140, ?, 252
A) 185
B) 189
C) 192
D) 195
E) 198
Question 4: What will come in place of the question mark (?) in the following series?
23, 24, ?, 153, 616, 3085
A) 47
B) 48
C) 49
D) 50
E) 51
Question 5: What will come in place of the question mark (?) in the following series?
648, 108, 324, 54, ?, 27, 81
A) 156
B) 164
C) 162
D) 148
E) 160

Tips & Tricks to Solve Wrong Number Series Quickly
Check the difference first
Always start by checking the difference between numbers. Differences will help you to a great extent in finding about the pattern involved. If the differences are close to each other and are following an increasing or decreasing pattern, the logic might be related to mathematical operators like addition or subtraction. If the differences are varying widly and are following an increasing or decreasing pattern, the logic might be related to mathematical operators like multiplication or division. On the other hand, if the differences are varying widly and sometimes increasing and sometimes decreasing there may be involvement of indices (such as squares, cube root etc.)
Solve the Previous Year’s Papers
Practising the previous year’s IBPS Clerk papers will give you an idea of the difficulty level of the wrong number series question. It also helps you understand which types are repeated most in the examination.
Practice regularly
Consistency is the key to mastering the wrong number series. The more you practice, the quicker you will recognise patterns and solve questions within seconds.
Conclusion
Wrong number series is a scoring topic in the IBPS Clerk 2025 exam. With regular practice and learning different patterns like AP, GP, square, cube and prime numbers, candidates can solve these questions in seconds.
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