Understanding Number Series: Types, Example, and Mock Test

“Number Series Shortcuts and Mind Tricks: Dear Readers, Quantitative Aptitude is one of the most important and high-scoring sections in any bank exam. A key topic under this section is Number Series, which involves an arrangement of numbers in a certain order, often containing missing or wrongly placed values. By applying the shortcuts and tricks provided in this resource (with examples), you can attempt these questions easily and with high accuracy. Practice more questions in the number series quiz by applying these methods. Revise these Number Series Shortcuts and Mind Tricks regularly to score better on this topic in your bank exams.”

Types of Number Series

Let us look at the various types of number series questions that may appear:

Addition Series: In this type of number series, specific numbers following a pattern are added to get the next number.

Subtraction Series: In this type of number series, specific numbers following a pattern are subtracted to get the next number.

Multiplication Series: In this type of number series, a particular number pattern is multiplied to obtain the next number.

Division Series: In this type of number series, a particular number pattern is divided to obtain the next number.

Square Series: In this type of number series, each number is a perfect square based on a particular pattern.

Cube Series: In this type of number series, each number is a perfect cube based on a particular pattern.

Fibonacci Series: In this type of number series, the next number is the sum of the two preceding numbers.”

Alternating Series: In this type of number series, multiple number patterns are used alternately to form the sequence.

Mixed Operator Series: In this type of number series, multiple mathematical operators are applied to generate the next number.

Arranging Numbers: In this type of number series, candidates must rearrange numbers as specified and then answer the related questions.

Solved Examples on Number Series Reasoning

1. Addition Series

Series: 3, 6, 9, 12, 15, ___
Pattern: Add 3 each time
Explanation:
3 + 3 = 6
6 + 3 = 9
9 + 3 = 12
12 + 3 = 15
Answer: 18

2. Subtraction Series

Series: 20, 17, 14, 11, ___
Pattern: Subtract 3 each time
Explanation:
20 − 3 = 17
17 − 3 = 14
14 − 3 = 11
Answer: 8

3. Multiplication Series

Series: 2, 6, 18, 54, ___
Pattern: Multiply by 3
Explanation:
2 × 3 = 6
6 × 3 = 18
18 × 3 = 54
Answer: 162

4. Division Series

Series: 64, 32, 16, 8, 4, ___
Pattern: Divide by 2
Explanation:
64 ÷ 2 = 32
32 ÷ 2 = 16
16 ÷ 2 = 8
8 ÷ 2 = 4
Answer: 2

5. Square Series

Series: 1, 4, 9, 16, 25, ___
Pattern: Perfect squares
1², 2², 3², 4², 5², …
Answer: 36 (6²)

6. Cube Series

Series: 1, 8, 27, 64, ___
Pattern: Perfect cubes
1³, 2³, 3³, 4³, …
Answer: 125 (5³)

7. Fibonacci Series

Series: 1, 1, 2, 3, 5, 8, ___
Pattern: Each number = sum of previous two
5 + 8 = 13
Answer: 13

8. Alternating Pattern Series

Series: 2, 4, 3, 6, 4, 8, 5, ___
Pattern:

• 1st pattern: +2 → 2, 4, 6, 8
• 2nd pattern: +1 → 3, 4, 5
  Next in 1st pattern: 6 + 2 = 8
  Answer: 8

9. Mixed Operator Series

Series: 5, 10, 9, 18, 17, 34, ___
Pattern: ×2, −1 (repeat)
5 × 2 = 10
10 − 1 = 9
9 × 2 = 18
18 − 1 = 17
17 × 2 = 34
Next: 34 − 1 = 33
Answer: 33

10. Arranging / Reordering Series

Series: 321, 432, 543, 654, ___
Pattern: Each number increases by adding 111
321 + 111 = 432
432 + 111 = 543
543 + 111 = 654
Answer: 765