Number Series For IBPS RRB PO & Clerk 2025 exam: Number series is an important topic in the Quantitative Aptitude section of IBPS RRB PO and Clerk exams. A number system is a mathematical value consisting of a number and a symbol. These questions frequently appear in all banking exams. In this article, we provide you with practice questions as well as tips and tricks to help you get faster at solving number series problems. By applying the strategies mentioned above, you can solve these questions quickly and accurately, thereby increasing your overall score in the Quantitative Aptitude section.
What is Number Series
A Number Series is a sequence of numbers arranged in a specific pattern or rule. The goal is to identify the logic behind the pattern and find the missing number or the next number in the series. These questions are common in RRB PO and Clerk Prelims and Mains Exam to test logical and analytical thinking. The pattern can be based on:
- Addition/Subtraction
- Multiplication/Division
- Squares/Cubes
- Prime Numbers
- Arithmetic + Geometric Combinations
- Alternating Patterns
- Pattern of Differences
- Double operations (e.g., ×2 + 1)
IBPS RRB PO and Clerk Full-Length Mock Tests & Topic Tests
To boost your preparation for the IBPS RRB PO/Clerk 2025 exam, start with topic tests – these help you strengthen individual topics like inequalities, syllogisms or puzzles by giving you focused practice. Once you are confident in the topics, move on to a full-length mock test and boost your question-solving speed and overall performance.
Tips & Tricks to Solve Number Series
- First and foremost, candidates must try & look for the given series such as addition, multiplication, subtraction or division etc.
- Given numbers are then to be arranged in that particular series to get the answer.
- For More preparation candidates take our free topic test and boost your preparation for the number system topic.
- Take the IBPS RRB Clerk and PO Previous year question paper and know the type of question asked in the IBPS RRB Clerk and IBPS RRB PO upcoming question paper.
Types of Number Series Asked in IBPS RRB PO/Clerk
- Missing Number Series
- Example: 2, 4, 8, ?, 32, 64
- Answer: 16 (Pattern: ×2)
- Wrong Number Series
- Example: 3, 6, 18, 72, 360, 2160
- Answer: 360 (Pattern: ×2, ×3, ×4, ×5, ×6 – but 360 doesn’t follow this)
- Mixed Operations
- Example: 1, 4, 9, 16, ?, 36
- Answer: 25 (Pattern: Square Numbers)
- Difference Pattern
- Example: 3, 8, 15, 24, 35, ?
- Answer: 48 (Pattern: +5, +7, +9, +11, +13)
- Alternate Series
- Example: 2, 5, 4, 9, 6, ?
- Answer: 13 (Odd positions: +2, +2; Even positions: +4)
Number Series Important Question for IBPS RRB PO and Clerk Exam
Question 1: The following numbers form a series. Find the odd one out.
80, 60, 20, 10, 5, 2.5
A) 80
B) 60
C) 20
D) 10
E) 5
Ans: 2
Solution:
80/2 = 40
40/2 = 20
20/2 = 10
10/2 = 5
5/2 = 2.5
Therefore, 40 should be in place of 60.
Hence, option b.
Question 2: The following numbers form a series. Find the odd one out.
86, 83, 77, 64, 41, -7
A) 64
B) 77
C) 86
D) 83
E) 41
Ans: 1
Solution:
86 – 3 = 83
83 – 6 = 77
77 – 12 = 65
65 – 24 = 41
41 – 48 = -7
Therefore, 65 should be in place of 64.
Hence, option a.
Question 3: The following numbers form a series. Find the odd one out.
9, 10, 14, 23, 40, 64
A) 9
B) 10
C) 14
D) 23
E) None of these
Ans: 5
Solution:
9 + 12 = 9 + 1 = 10
10 + 22 = 10 + 4 = 14
14 + 32 = 14 + 9 = 23
23 + 42 = 23 + 16 = 39
39 + 52 = 39 + 25 = 64
Therefore, 39 should be in place of 40.
Hence, option e.
Question 4: The following numbers form a series. Find the odd one out.
3, 5, 8, 12, 17, 24
A) 8
B) 12
C) 24
D) 5
E) 17
Ans: 3
Solution:
3 + 2 = 5
5 + 3 = 8
8 + 4 = 12
12 + 5 = 17
17 + 6 = 23
Therefore, 23 should be in place of 24.
Hence, option c.
Question 5: The following numbers form a series. Find the odd one out.
1, 3, 7, 15, 30, 63
A) 30
B) 3
C) 7
D) 63
E) 15
Ans: 1
Solution:
1 × 2 + 1 = 3
3 × 2 + 1 = 7
7 × 2 + 1 = 15
15 × 2 + 1 = 31
31 × 2 + 1 = 63
Therefore, 31 should be in place of 30.
Hence, option a.
Question 6: What will come in place of the question mark (?) in the following series?
23, 38, 68, 113, ?, 248
A) 151
B) 162
C) 173
D) 184
E) 155
Ans: 3
Solution:
The series follows the pattern:
23 + 15 × 1 = 38,
38 + 15 × 2 = 68,
68 + 15 × 3 = 113,
113 + 15 × 4 = 173,
173 + 15 × 5 = 248.
Hence, option c.
Question 7: What will come in place of the question mark (?) in the following series?
250, 249, 241, 214, ?, 25
A) 164
B) 150
C) 188
D) 172
E) None of these
Ans: 2
Solution:
The series follows the pattern:
250 – 13 = 249,
249 – 23 = 241,
241 – 33 = 214,
214 – 43 = 150,
150 – 53 = 25.
Hence, option b.
Question 8: What will come in place of the question mark (?) in the following series?
140, 150, 170, 210, 290, ?
A) 510
B) 380
C) 540
D) 430
E) 450
Ans: 5
Solution:
The series follows the pattern:
140 + 10 = 150,
150 + 20 = 170,
170 + 40 = 210,
210 + 80 = 290,
290 + 160 = 450.
Hence, option e.
Question 9: What will come in place of the question mark (?) in the following series?
472.5, ?, 105, 60 ,40 , 32
A) 210
B) 240
C) 250
D) 265
E) None of these
Ans: 1
Solution:
The series follows the pattern:
472.5 / 2.25 = 210,
210 / 2 = 105,
105 / 1.75 = 60,
60 / 1.5 = 40,
40 / 1.25 = 32.
Hence, option a.
Question 10: What will come in place of the question mark (?) in the following series?
33, 34, 70, 213, 856, ?
A) 3245
B) 3664
C) 4285
D) 4675
E) 4854
Ans: 3
Solution:The series follows the pattern:
33 × 1 + 1 = 34,
34 × 2 + 2 = 70,
70 × 3 + 3 = 213,
213 × 4 + 4 = 856,
856 × 5 + 5 = 4285.
Hence, option c.
Related Blogs
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IBPS RRB PO Previous Year Question Papers |
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Speed up Number Series For IBPS RRB PO/Clerk 2025 FAQ
number series is a sequence of numbers that follows a certain pattern.
Typically, 5 questions on number series are asked in the Reasoning or Quantitative Aptitude section of the Prelims.
Spend less than 1 minute on each question.
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