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  • Early Years Foundation Stage

A Right Charlie

Age 7 to 11
Challenge Level Yellow starYellow star
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A Right Charlie


Charlie's house number is a three-digit square number.

This number when reversed is also a square and is Charlie's telephone extension at work.

His car registration number is  a four-digit square number and is formed from his house number by repeating the right hand digit.

What is Charlie's house number?


Why do this problem?

This problem requires systematic working and will increase children's familiarity with square numbers.


Key questions

What three-digit square numbers do you know?
How do you know you haven't missed out any three-digit square numbers?

Possible extension

Some pupils may enjoy the challenge of Gran, How Old Are You? which is a similar numerical problem.

Possible support

Many children will find the use of a calculator invaluable for this problem.

 

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Special 24

Find another number that is one short of a square number and when you double it and add 1, the result is also a square number.

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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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