Step 6 Objective

Begin to use linear expressions to describe the nth term of an arithmetic sequence, justifying its form by referring to the activity or practical context from which it was generated.

Examples of what pupils should know and be able to do

Generate sequences from practical contexts, including:

Probing questions

What did you look for in your sequence to help you find the nth term?
How does this link to ... ? (Use the context that generated the sequence.)

Probe further to get pupils to justify specific parts of the generalisation – e.g. explain why 'multiply by 4' is part of your nth term.

What if pupils find this a barrier?

Use and adapt further examples from FTM(S) pp. 154-156 - Acrobat pdf document (52Kb) for pupils to generate and explore terms of sequences.
Keep to linear sequences and get pupils to build up the pattern using equipment or by drawing on paper.
Help pupils to see the link between a constant difference in the sequence and the multiplier in the nth term.