Percentages

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Roasting old chestnuts 4

For teachers. Yet more school maths from long ago-interest and percentages.
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Activities on the Gattegno chart

In this article, Alf outlines six activities using the Gattegno chart, which help to develop understanding of place value, multiplication and division.
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Pied Piper

Age

14 to 16

Challenge level

How many rats did the Pied Piper catch?
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Porridge

Age

14 to 16

Challenge level

To make porridge, Goldilocks mixes oats and wheat bran..... what percentage of the mix is wheat?
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Better spelling

Age

11 to 14

Challenge level

Weekly Problem 12 - 2010
Can Emily increase her average test score to more than $80$%? Find out how many more tests she must take to do so.
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Trusting the tabloids

Age

11 to 16

Challenge level

Can you match the cards and figure out whether the tabloid headlines can be trusted?
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Circle packing

Age

14 to 16

Challenge level

Equal circles can be arranged so that each circle touches four or six others. What percentage of the plane is covered by circles in each packing pattern? ...
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Round and round

Age

14 to 16

Challenge level

Prove that the shaded area of the semicircle is equal to the area of the inner circle.
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Mathland election

Age

11 to 14

Challenge level

A political commentator summed up an election result. Given that there were just four candidates and that the figures quoted were exact find the number of votes polled for each candidate.
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Antifreeze

Age

14 to 16

Challenge level

How much more antifreeze is needed to make the proportion 30%?