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### Number and algebra

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### Working mathematically

### For younger learners

### Advanced mathematics

# To Iff or Not to Iff?

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River Crossing

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Iffy Logic

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The Tour De Clochemerle

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Iff

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Mind Your Ps and Qs

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In this feature you will find a selection of problems that will require you to reason logically. You will also be introduced to the symbols $\implies$ and $\iff$ and be challenged to use these to create true statements.

Plus magazine has a selection of interesting articles looking at logic, mathematical logic, its role in computer science and the philosophy of maths, and on how it's being used in applications.

Age 11 to 18

Challenge Level

There is nothing half so much worth doing as simply messing about in boats...

Age 14 to 18

Challenge Level

Can you rearrange the cards to make a series of correct mathematical statements?

Age 14 to 18

Challenge Level

Can you work out where these 5 riders came in a not-quite-so-famous bike race?

Age 14 to 18

Challenge Level

Take a triangular number, multiply it by 8 and add 1. What is special about your answer? Can you prove it?

Age 16 to 18

Challenge Level

Sort these mathematical propositions into a series of 8 correct statements.