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Penta Primes

Age 7 to 11
Challenge Level Yellow starYellow starYellow star
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Here are ten cards numbered 0 to 9:

cards numbered 0-9

Using all ten cards, rearrange them to make five prime numbers.

Can you find a way of doing it with five two-digit numbers?

How about using one one-digit number, one three-digit number and three two-digit numbers? ...

This problem is based on an idea from Mathematical Challenges for Able Pupils Key Stages 1 and 2, published by DfES.


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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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