Examples of what pupils should know and be able to do
Use known facts such as 
= 0.125 to convert fractions to decimals mentally,
for example:
= 0.125 – 5 = 0.625
Use mental strategies for calculating fractions and percentages, for example:
of 20
- 35% of 40
Use mental skills to solving simple problems, for example:
- A person's heart beats 70 times in a minute. How many times does it beat in an hour?
- Two years ago Jim was 1.48 metres tall. Now Jim's height is 1.7 metres. How much has Jim grown?
- FTM(P)Y456 p 93 - Acrobat pdf document (18Kb)
- FTM(P)Y456 p 97 - Acrobat pdf document (31Kb)
- FTM(P)Y456 p 99 - Acrobat pdf document (18Kb)
- FTM(P)Y456 p 101 - Acrobat pdf document (27Kb)
Probing questions
How do you decide whether you can do a calculation mentally? What do you look for?
How would you do this division mentally? e.g. 420 ÷ 15
is 0.125 as a decimal. What other decimal equivalents can you find from this?
What percentages of quantities can you easily work out in your head?
How would you go about estimating a square root, for example, of 30?
What if pupils find this a barrier?
Use similar strategies to those suggested in Step 5.
- Securing L5 in year 9 intervention lesson 9N1.3, 9N1.4. - Acrobat pdf document (57Kb) These two lessons include useful paired and group activities for pupils to discuss and explain mental methods of calculation. The resources could be easily adapted.
<< Previous Step | Next Step >>