Creating convincing arguments or "proofs" to show that statements are always true is a key mathematical skill. The problems in this feature offer you the chance to explore number patterns and create proofs to show that these are always true.

Many of the problems in this feature include proof sorting activities which challenge you to rearrange statements in order to recreate clear, rigorous proofs.

The last day for sending in your solutions to the live problems is Monday 31 January.

Plus magazine has a selection of interesting articles about proofs here.

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Take three consecutive numbers and add them together. What do you notice?

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How many sets of three consecutive odd numbers can you find, in which all three numbers are prime?

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Is there a quick and easy way to calculate the sum of the first 100 odd numbers?

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What can we say about all the primes which are greater than 3?

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If you take four consecutive numbers and add them together, the answer will always be even. What else do you notice?

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Take four consecutive whole numbers. Multiply the first and last numbers together. Multiply the middle pair together. What do you notice?

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Which numbers cannot be written as the sum of two or more consecutive numbers?

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$40$ can be written as $7^2 - 3^2.$ Which other numbers can be written as the difference of squares of odd numbers?