# Number Series

**Number series** is a sequential arrangement of numbers following a certain defined pattern. There is no set pattern and each question in number series may follow a different type of pattern or sequential arrangement of letters or digits, which need to detect using their common sense and reasoning ability.

## Some Important Patterns of Number Series:

- Series with an increasing difference
- Series with a constant difference
- Series with decreasing difference
- Perfect squares and cubes of numbers’ series

**Types of Number Series **

- Addition Number Series: In this type of number series, specific numbers based on some pattern are added to get the next number.
- Subtraction Number Series: In these type of number series, specific numbers based on some pattern are subtracted to get the next number.
- Multiplication Number Series: In this type of number series, a particular type of number pattern is multiplied to get the next number.
- Division Number Series: In these type of number series, a particular type of number pattern is divided to get the next number.
- Square Number Series: In square number series, each number is a perfect square of a particular number pattern.
- Cube Number Series: In these type of number series, each number is a perfect cube of a particular number pattern.
- Arithmetic Series: When the differences between the successive numbers given in the series is the same.
- Geometric Series: When each successive number in the series is obtained by multiplying or dividing the previous one by a fixed number.
- Fibonacci Number Series: In this type of number series, the next number is the addition of two previous numbers.
- Alternating Number Series: In these type of number series, multiple number patterns are used alternatively to form a series.
- Mixed Operator Number Series: In this type of number series, multiple operators are applied to get the next number in the series.
- Arranging Number Series: In these type of number series, need to rearrange numbers, as specified, and then answer the given questions.

Example : Find the missing term.

5, 6, 9, 14, 21, ?

Solution : 30

Example : Find the missing term.

40, 30, 22, 16, ?

Solution : 12

Example : Find the missing term.

32, 19, 8, ?

Solution : 1

Example: Find the missing term.

1, 3, 9, 27, 81, ?

Solution : 243

Example : Find the missing term.

1, 2, 6, 15, 31, ?

Solution : 56

Example : Find the missing term.

225, 100, 36, 9, 1, ?

Solution : 0

Example : Find the missing term.

13, 25, 51, 101, 203, ?

Solution : 405

Example : Find the missing term.

3, 8, 6, 14, ?, 20

Solution : 12