Step 3 Objective
Find differences by counting up through next multiple of 10, 100 or 1000, e.g. calculate mentally a difference such as 8006 – 2993.
- Examples of what pupils should
know and be able to do - Probing questions
- What if pupils find
this a barrier?
What if pupils find this a barrier?
Pupils may need to go back to calculating easier differences using a number line.
It is important for pupils to be able to visualise an appropriate part of a number line so they can recognise when numbers are close to a multiple of 10, 100 or 1000. Ask pupils to imagine a number line and to locate specific numbers on it. Progressively ask pupils to identify the numbers they need on their number line to be able to find the difference.
Counting on and back ITP - Zip file (456Kb)
Number Line ITP - Zip file (459Kb) will form a useful visual image to support pupils' mental calculations
Refer to Teaching mental calculation strategies to L5 - Acrobat pdf document (554Kb) pages 31-44.
Refer to Teaching mental calculation strategies to L5 - Acrobat pdf document (554Kb) pages 15-30.