A Right Charlie

'A Right Charlie' printed from https://nrich.maths.org/

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?

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

What three-digit square numbers do you know?

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

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

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