# 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. Take a bow postpeople!

The Postman Algebra Challenge involves replacing housenumbers 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 housenumbers. Our results were as follows:

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

A 100% success rate! Well done to the posties for successfully solving the equations! For our next batch of letters 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 solvable with only basic maths knowledge. It shows a worrying lack of what we would call fundamental knowledge among our peers. But worst of all our friends never received the letters we sent them containing the antidotes they so desperately needed to cure them from their terrible diseases. Sadly, as a result, they have since 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; for once your letter will stand out. 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.

A word of warning, however, as the Postman Algebra Challenge is not suitable for all your letters. For example, we would advise against using this method to post ransom notes to rich people after kidnapping their children; it doesn't portray the right cut-throat image so it's unlikely you'll be taken seriously and you'll never see the money you demanded. And then of course you'd have go through with your threats to kill the children, which would be a shame.

Whatever your reason to partake in the Postman Algebra Challenge, we wish you and the postie the best of luck!