Tag Archives: decrease

210. Most Wanted Percentages

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I’ve been looking at how to teach percentage increase and decrease at Key Stage 3. If you can find 20%, you can obviously increase by 20% by adding it on. But does this reinforce the misconception that percentages are an addition, rather than multiplicative, function? I’ve started teaching multipliers for increase and decrease to a wider range of pupils, so it makes sense to introduce the concept earlier. I’ve used finding 120% as a way to increase by 20%. It opens up discussion as to why this works and pupils can form their own ideas on how to decrease.

muppets

Image Credit: www.te

To reinforce and practice the idea of increase and decrease by percentages I’ve created some ‘Muppets’ themed Top Trumps cards (not licensed). You can download them here: Muppets Top Trumps (pdf)

There are only eight cards, but you could print out one set per pupil and shuffle them.

157. Receipt for learning

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Do you ever really look at the bottom of your supermarket receipts?

This caught my eye today:

image

The bill is broken down into three bands of tax, the relevant amounts, VAT and total amount payable.

It would be quite an easy task to enlarge a receipt on a photocopier and blank out quantities. Don’t forget to blank out financial transaction details. You could work out percentages of amounts, reverse percentages or find missing percentages. It could be extended to percentage increase using multipliers. It also links to decimal calculations, rounding and money.

All this learning from a bit of paper from the supermarket*.

*Not all supermarkets do this, but there is usually some kind of tax reference.