The Postman Algebra Challenge

Now that's a phrase you don't hear everyday. We hope the postmen and postwomen who inadvertently took part in this challenge found it both amusing and educational. And not annoying. Take a bow, postpeople.

The Postman Algebra Challenge involves replacing house numbers on envelopes with algebraic equations so that the postie has to solve it in order to deliver the letter. For example, instead of addressing a letter to '22 High Street', write 'X High Street' and at the bottom of the envelope write 'where X = 2 x 10 + 2'.

Any letter of the alphabet can be used to stand for the unknown quantity but we chose the letter 'X' as its use in algebraic equations is widespread. We think using a different letter would just, ahem, confuse people.

We began the challenge by sending letters to friends all around the country using simple algebraic equations instead of house numbers. Their full addresses are not displayed below. Our results were as follows:

• The aforementioned X High Street, where X = 2 x 10 + 2 was delivered successfully to number 22.
• X Harold Lane, where X = 2 x 10 + 5 was delivered successfully to number 25.
• X Lake Road, where X = 5 x 10 + 9 was delivered successfully to number 59.

A 100% success rate! Well done to the posties for successfully solving the equations. For the next batch of letters we sent to our friends we increased the complexity a notch and our results were as follows:

• X London Road, where X = 5 ² was NOT delivered to number 25.
• X Park Place, where X = 5 ² + 3 was NOT delivered to number 28.
• X Goodwood Street, where X = 55 x 10 + 3 was NOT delivered to number 553.

A 100% failure rate! We were disappointed with the posties' efforts because the equations are easily solvable with only basic maths knowledge. It highlights real concerns for us about the standard of our education system. But worst of all our friends never received the antidotes they so desperately needed to cure them from their terrible diseases. As a result they have sadly perished. I don't know how the posties can live with themselves.

We also used a non-algebra puzzle for one final attempt, which technically was part of our Postman Non-Algebra Challenge. This was again with the number 22, but this time masquerading as: 'a numerical representation of two little ducks'. This letter was successfully delivered so well done postie!

Now you can take part in the Postman Algebra Challenge and entertain yourself and posties all around the world. Try it for your Christmas cards next year. Or for your next stern letter to the Prime Minister, addressed to X Downing Street, where X = 26 + 9 - 18 + 14 - 21; your letter will finally stand out for once.

And what better way to apply for the vacant maths teacher job at your local school than with a quadratic equation in the address; sure to impress your potential new employers; if it reaches them, that is.