article
Where do we get our feet wet?
Professor Korner has generously supported school mathematics for more than 30 years and has been a good friend to NRICH since it started.
Explaining, convincing and proving
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articleTelescoping functions
Take a complicated fraction with the product of five quartics top and bottom and reduce this to a whole number. This is a numerical example involving some clever algebra. -
articleA knight's journey
This article looks at knight's moves on a chess board and introduces you to the idea of vectors and vector addition. -
articleGeometry and gravity 2
This is the second of two articles and discusses problems relating to the curvature of space, shortest distances on surfaces, triangulations of surfaces and representation by graphs. -
articlePythagorean triples II
This is the second article on right-angled triangles whose edge lengths are whole numbers.
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articlePythagorean triples I
The first of two articles on Pythagorean Triples which asks how many right angled triangles can you find with the lengths of each side exactly a whole number measurement. Try it!
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interactivityProof sorter - sum of an arithmetic sequence
Age16 to 18Challenge level
Put the steps of this proof in order to find the formula for the sum of an arithmetic sequence -
interactivityProof sorter - the square root of 2 is irrational
Age16 to 18Challenge level
Try this interactivity to familiarise yourself with the proof that the square root of 2 is irrational. Sort the steps of the proof into the correct order. -
interactivityProof sorter - geometric sequence
Age16 to 18Challenge level
Can you correctly order the steps in the proof of the formula for the sum of the first n terms in a geometric sequence? -
interactivityProof sorter - quadratic equation
Age14 to 18Challenge level
This is an interactivity in which you have to sort the steps in the completion of the square into the correct order to prove the formula for the solutions of quadratic equations.