Number sequences are sets of numbers that follow **a pattern or a rule**.

Each number in a sequence is called a **term**.

The **term to term rule** of a sequence describes how to get from one term to the next.

Work out the next two terms in the following sequence and write down the term to term rule:

3, 7, 11, 15, ...

Firstly, work out the difference in the terms.

This sequence is going up by four each time, so add 4 on to the last term to find the next term in the sequence.

3, 7, 11, 15, **19**, **23**, ...

To work out the term to term rule, give the starting number of the sequence and then describe the pattern of the numbers.

The first number is 3. The term to term rule is 'add 4'.

Once the first term and term to term rule are known, all the terms in the sequence can be found.

Work out the next two terms in the following sequence and write down the term to term rule:

-1, -0.5, 0, 0.5, ...

The first term is -1. The term to term rule is 'add 0.5'.

- Question
What is the term to term rule and the next two terms of the sequence: 17, 14, 11, 8, ...?

To work out the term to term rule, give the first term and then the pattern. The first term is 17, and the pattern is to subtract 3 each time, so the term to term rule is 'start at 17 and subtract 3'.

The next two terms of the sequence are 5 and 2, giving the sequence as:

- Question
What are the first four terms of a sequence that starts with 1, and has a term to term rule of multiply by 2?

The first term is given as 1. Each number that follows is double the number before.