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Stretching Fractions

Age 14 to 16
Challenge Level Yellow starYellow starYellow star
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This problem benefits from a systematic treatment.

Please see the Hint for useful categories when constructing a systematic approach.

The interest in this problem is the structure not simply the results - where do the various start fractions go to and why?

An article that examines this problem in more depth can be found here.


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Converging Means

Take any two positive numbers. Calculate the arithmetic and geometric means. Repeat the calculations to generate a sequence of arithmetic means and geometric means. Make a note of what happens to the two sequences.

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The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.

NRICH is part of the family of activities in the Millennium Mathematics Project.

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