Numbers and sequences
Sequences
A sequence is a list of numbers that follow a rule. In a linear sequence, you add or subtract the same amount each time ā the term-to-term rule.
Working with sequences
ā¢ Find the next term by using the term-to-term rule (e.g. 'add 4'). ā¢ Count back through zero into negative numbers if you keep subtracting. ā¢ To find a later term quickly, start at the first term and add the right number of jumps.
Worked examples
Finding the next term
- The sequence is 5, 9, 13, 17, ā¦
- The rule is 'add 4'.
- 17 + 4 = 21.
Answer: The next term is 21.
Finding a later term
- First term 1, rule 'add 4'. Find the 10th term.
- From the 1st to the 10th is 9 jumps of 4.
- 1 + 9 Ć 4 = 1 + 36 = 37.
Answer: The 10th term is 37.
Where you see this in real life
- The number of pancakes you get from each cup of mix (8, 16, 24 ā¦).
- Counting money saved by the same amount each week.
- A repeating flashing pattern on a lighthouse.
Key words
- Sequence
- A list of numbers that follow a rule.
- Term
- One of the numbers in a sequence.
- Term-to-term rule
- The rule that gets you from one term to the next, e.g. 'add 4'.