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What Is a Sequence in Mathematics

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Sequence Definition Formula Types and Solved Examples

Do you know how to predict which number comes next in a series of numbers? Well, patterns are all around us. Patterns can be repeated items, shapes, colours, images, or numbers. Sometimes a set of things is repeated to create a pattern. Number patterns are fun because you need to look carefully for clues to complete them. If you are intrigued and want to know what number sequence is or how you can identify a pattern, continue reading through the content below.


So, what is the number sequence? Let’s understand with the help of simple activities given below.


Activity

Here is a number pattern, or a sequence of numbers. Find out what comes next?

1, 2, 3, 4, 5, __

This is a fairly easy pattern because we count this one all the time. It’s 6.

The number 6 completes this pattern.


Here is another one.

Let’s find the next number by following the pattern 2, 4, 6, 8, ___.

We have 2, 4, 6, 8. If you look for clues, we see that each number in this sequence exceeds its previous number by 2. That’s the clue.

⇒ 2 + 2 is 4.

⇒ 4 + 2 is 6.

⇒ 6 + 2 is 8.

We should add 2 to 8 to give us the next number. Therefore, the next number is 10.


Number patterns can also work in reverse.


Number Pattern

Number Pattern


When you look closely, you will see that the numbers are decreasing. It means that in this pattern, the numbers are not adding on. It's subtracting.


Number Pattern

Number Pattern


30 − 3 is 27.

27 − 3 is 24.

24 − 3 is 21.

21 − 3 is 18.

81 − 3 is 15.


Things to Remember

  • Number pattern: These are the numbers that follow a particular sequence or pattern.

  • Growing pattern: If the numbers are getting bigger, then it is a growing pattern.

  • Shrinking pattern: If the numbers are getting smaller, then it will be a shrinking pattern.

  • Repeating pattern: When the same number grouping is observed over and over again.


Types of Sequences

There are different types of sequences based on the pattern among the terms. The following are the most familiar sequences.


1. Arithmetic Sequence:

In an arithmetic sequence, the common difference between any two successive terms remains the same. Note the common difference can be either negative or positive.

For example: 5, 10, 15, 20, 25, 30, ...

In this example, the common difference between any two successive terms is 5.


Arithmetic Sequence


Arithmetic Sequence


2. Geometric Sequence:

A geometric sequence is one in which the common ratio of any two successive terms is the same. Multiplying the first term with the common ratio gives the second term and multiplying the second term with the common ratio gives the third term and so on.

For example: 2, 4, 8, 16, 32, 64…

Here, the common ratio between any two successive terms is 2.


Geometric Sequence


Geometric Sequence


3. Harmonic Sequence:

A sequence is said to be a harmonic sequence if the reciprocals of the terms are in an arithmetic sequence.

For example: $\frac{1}{5}, \frac{1}{10}, \frac{1}{15}, \frac{1}{20}, \frac{1}{25}, \frac{1}{30},....$

If you take the reciprocals of each term in this sequence, we get 5, 10, 15, 20, 25, 30, … which are in an arithmetic sequence.


4. Fibonacci Sequence:

Fibonacci numbers are a fascinating number series in which each element is created by adding two preceding elements, with the sequence beginning with 0 and 1. The first term is 0 and the second term is 1. The third term will be obtained by adding the first and second term which is equal to 0+1 = 1. The fourth term will be equal to the sum of the third and second terms, i.e., 1 + 1 = 2, and so on.


Fibonacci Sequence


Fibonacci Sequence


Conclusion

Number sequencing is a process in a child's development of number sense. This is because it involves calculating, thinking, and reasoning. The steps, however, can be confusing to children. So, rather than forcing children to take a compulsive learning course, we can involve them in pleasant games and activities to make learning easier. Children can master arithmetic reasoning if they are familiar with numerical sequencing. To teach your young ones similar Maths topics in a fun way and help create a strong mathematical base, visit our website now.

FAQs on What Is a Sequence in Mathematics

1. What is a sequence in Maths?

A sequence is an ordered list of numbers that follow a specific rule or pattern. Each number in a sequence is called a term.

  • The first number is called the first term.
  • The position of a term is indicated by its index (1st, 2nd, 3rd, etc.).
  • Sequences can follow patterns like adding, subtracting, multiplying, or more complex rules.
Example: 2, 4, 6, 8, ... is a sequence where each term increases by 2.

2. What are the different types of sequences?

The main types of sequences in Maths are arithmetic, geometric, and special sequences.

  • Arithmetic sequence: The difference between consecutive terms is constant.
  • Geometric sequence: The ratio between consecutive terms is constant.
  • Fibonacci sequence: Each term is the sum of the previous two terms.
These types are commonly studied in algebra and number patterns.

3. What is an arithmetic sequence?

An arithmetic sequence is a sequence in which the difference between consecutive terms is constant.

  • The constant difference is called the common difference (d).
  • Formula for the nth term: aₙ = a + (n − 1)d.
  • Example: 5, 8, 11, 14,... where d = 3.
Arithmetic sequences are also known as linear sequences.

4. What is a geometric sequence?

A geometric sequence is a sequence where each term is obtained by multiplying the previous term by a constant number.

  • This constant number is called the common ratio (r).
  • Formula for the nth term: aₙ = arⁿ⁻¹.
  • Example: 3, 6, 12, 24,... where r = 2.
Geometric sequences model exponential growth or decay.

5. What is the formula for the nth term of a sequence?

The nth term formula gives a rule to calculate any term in a sequence without listing all terms.

  • For an arithmetic sequence: aₙ = a + (n − 1)d.
  • For a geometric sequence: aₙ = arⁿ⁻¹.
Here, a is the first term, d is the common difference, r is the common ratio, and n is the term position.

6. How do you find the next term in a sequence?

To find the next term in a sequence, identify the pattern or rule being followed.

  • Check the difference between terms (addition/subtraction).
  • Check the ratio between terms (multiplication/division).
  • Look for repeating or increasing patterns.
Example: In 4, 7, 10, 13,... the pattern is +3, so the next term is 16.

7. What is the difference between a sequence and a series?

A sequence is an ordered list of numbers, while a series is the sum of the terms of a sequence.

  • Sequence example: 1, 2, 3, 4
  • Series example: 1 + 2 + 3 + 4 = 10
In short, a sequence lists numbers, and a series adds them together.

8. Can you give an example of a sequence?

An example of a sequence is 1, 4, 9, 16, 25, which follows a square number pattern.

  • Each term is the square of its position.
  • nth term formula: aₙ = n².
  • The 6th term is 6² = 36.
This is called a quadratic sequence.

9. What is a finite and infinite sequence?

A finite sequence has a limited number of terms, while an infinite sequence continues indefinitely.

  • Finite example: 2, 4, 6, 8 (ends at 8).
  • Infinite example: 1, 2, 3, 4,... (continues forever).
Infinite sequences are often written using ellipses (...).

10. Why are sequences important in Maths?

Sequences are important in Maths because they help describe patterns, model real-life situations, and form the basis of series and calculus concepts.

  • Used in algebra to find nth terms.
  • Used in finance for interest calculations.
  • Used in science to model growth and decay.
Understanding sequences builds a strong foundation for higher-level mathematics.