There are a few ways of learning how to calculate percentages of whole numbers ..
.. although this video shows how to calculate percentages by converting to fractions and then cross division.
‘Percentage’ means ‘out of 100.’ Therefore we can use the idea of ‘equivalent fractions’ to make the numbers smaller and easier to deal with.
So 12% is exactly the same as 12/100; which is equivalent to 6/50 or 3/25.
Any number can be written as divided by 1.
So 50 is the same as 50/1 – we then use cross division to make a calculation.
The key points to remember are:
- ‘whatever we do to the top, we have to do to the bottom.’
- don’t forget that ‘of” always means ‘multiply.’
Finally, not all questions require you to answer as a decimal – it’s perfectly OK to leave as a fraction (providing you make sure it’s as small as possible).
This is a popular method that is taught in schools:
Why are percentages important?
Most of everyday life involves percentages, usually as a comparison.
For instance 30% discount seems a much better deal than 10%… or does it? (you really need to work out the actual price you pay).
Generally we tend to mix and match between fractions and percentages. Although it’s the same thing, 30% seems a lot friendlier than a discount of 3/10ths !
Watch the videos on YouTube:
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