Examples of what pupils should know and be able to do
Use mental methods. For example find:
- 10% of £20 by dividing by 10;
- 5% of £5 by finding 10% and then halving;
- 15% of 40 by finding 10% then 5% and adding the results together;
of 24?
Use informal written methods, including using jottings. For example find:
- 11% of £2800 by calculating 10% and 1% and adding the results together;
- 70% of 130 g by calculating 10% and multiplying this by 7 or by calculating 50% and 20%.
- FTM(P) Y456 page 33 - Acrobat pdf document (23Kb)
- Sorting fractions and percentages example of pupil's work - Acrobat pdf document (240Kb)
- Percentage test question - Rtf (rich text format) document (59Kb)
Probing questions
What percentages can you easily work out in your head? Talk me through a couple of examples.
When calculating percentages of quantities, what percentage do you usually start from?
How do you use this percentage to work out others?
To calculate 10% of a quantity, you divide it by 10. So to find 20%, you must divide by 20. What is wrong with this statement?
Using a 1-100 grid, 50% of the numbers are even. How would you check?
Give me a question with the answer 20%.
What if pupils find this a barrier?
Help pupils make connections between finding simple percentages of whole-number quantities by using a spider diagram.
Ask pupils to write, for example, 52 = 100% in the middle of a piece of paper and then link together other percentages that they can find (e.g. 26 = 50%, 13 = 25%, 5.2 = 10%, etc.).
Use the visual image of the Number Grid ITP - Zip file (462Kb) to discuss parts in every 100.
Use Fractions ITP - Zip file (457Kb) with the percentages shown.
Practise using TMCS to L5 loop cards set 14 - Acrobat pdf document (25Kb).
<< Previous Step | Next Step >>