7.5.1

Find the nth Term

Test yourself

Finding the 'nth Term'

When you are asked to find the ‘nth term’, you are being asked to find a rule that can be used to find the value of any step in a particular sequence.

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How to find the nth term

  • You need to find a rule that takes you from the step number to the corresponding number in the sequence.
    • So you need to find a rule that takes 1 to 5, 2 to 7, 3 to 9 and so on.
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Work out the sequence difference

  • First, work out the difference between the numbers in the sequence. This tells you how much you need to multiply 'n' by.
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Multiply by 2

  • The difference between the numbers in the sequence is 2.
    • So the first part of the rule is 'multiply by 2'.
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Add 3

  • Next, work out what you need to add or subtract to get the number in the sequence.
    • To get from 2 to 5, add 3. So the second part of the rule is 'add 3'.
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2n+3

  • In algebra, we write the rule 'multiply by 2 and add 3' as 2n + 3 (we do not use the multiplication sign). This is the ‘nth term’.

Jump to other topics

1Angles

2Fractions

3Time

4Prime Numbers

4.1Prime Numbers

5Probability

6Ratio

6.1Ratios

7Sequences

8Area & Perimeter

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