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Nim

Start with any number of counters in any number of piles. 2 players take it in turns to remove any number of counters from a single pile. The loser is the player who takes the last counter.

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Latin Numbers

Can you create a Latin Square from multiples of a six digit number?

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Back to Basics

Find b where 3723(base 10) = 123(base b).

Composite Notions

Stage: 4 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

A composite number is one that is neither prime nor 1.

Show that 10201 is composite in any base.

Likewise show that 10101 is composite in any base.

Further Reading: Learn About Number Bases by Toni Beardon


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. More information on many of our other activities can be found here.
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