Examples of what pupils should know and be able to do
Use jottings to support, record and explain partial mental methods, building on existing mental strategies.
Annotate blank number lines to support these mental calculations.
Probing questions
What jottings do you find useful when adding/subtracting? Do you use a number line? What do you record on the number line?
Can you give me some examples of the sorts of calculations that are easier with jottings?
What if pupils find this a barrier?
Mathematics challenge 1 and 2 - Acrobat pdf document (354Kb) focus on mental addition and subtraction using number lines.
Teaching mental calculation strategies to level 5 - Acrobat pdf document (554Kb) includes a useful section on jottings: pp. 11-12.
Pupils are likely to benefit from exploring the use of number lines for these calculations. Emphasise that number lines are used so that calculations can be broken down into steps that can easily be done mentally.
For guidance on informal methods leading to efficient written methods refer to the document 'The National Numeracy Strategy: Teaching written calculations – guidance for teachers at Key Stages 1 and 2' (QCA/99/486) pp. 19-32.