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For younger learners

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Number of Arms

Age 11 to 14
ShortChallenge Level Yellow starYellow starYellow star
Secondary curriculum
  • Problem
  • Solutions

How likely is it that the next person you meet has an above average number of arms, where...

a) average means 'mean'?
b) average means 'mode'?
c) average means 'median'?


This problem is adapted from the World Mathematics Championships
You can find more short problems, arranged by curriculum topic, in our short problems collection.

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When Kate ate a giant date, the average weight of the dates decreased. What was the weight of the date that Kate ate?

Balancing the Books

How many visitors does a tourist attraction need next week in order to break even?

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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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