The 14th of March, we are told, is π day because that the beginning of that amazing number in decimal notation is 3.14.

I’m not sure how you celebrate π day. Dance round in circles? Go on and on (as many of us are wont to do) without ever repeating ourselves (not something I can do).

On the basis of the photos I have seen, some people bake pies for π day. If you bake a tiny pie with a one inch diameter its circumference will be π inches. Even more π-like would be to make a pie whose *area *is π but I am not going to try and do the maths.

Furthermore, if you cut an apple in two horizontally to make a circular section then, if you attribute the value of *one apple *to the diameter, the circumference will be equal to *1 apple π.
*

Even though π day is a laudable institution, I have a couple of quibbles.

First of all, 3.14 is the 14th of March according to the American date format. It is slightly ironical to celebrate ones of the most spectacular entities in matematics on the basis of a system which so __un__mathematical. Month-day-year for a date is like writing a number in the format tens-units-hundreds. A year, in this system, would have 653 (sixty-five-three hundred days). What about using the more mathematical European format then, which goes from smallest to largest. Well, it does, I think, reflect the nature of π more effectively. Because π is a baffling number and if you read its first three digits according to the European format you come up with a baffling date: the 31st of April, which doesn’t usually exist. In fact you could even call it a transcendental date.

You could say that the 31st of April is simply the day which follows the 30th of April, namely the 1st of May. Or you could say that since you’ve called it April it has to stay in April and would therefore be the next April day after 30 April, which would be the 1 first of April of the following year. Whether that day ever materialises is a moot point, though – some people might argue that, like the horizon, we would never reach it, because it constantly be one year ahead of you.

My second objection is the following If you’re celebrating the 14th of March you’re celebrating 3.14 But π is not 3.14! If it were there would be nothing special about, it would be no different from 6.48 or 9.21. Π is a number which goes on and on and never repeats itself and which, it is suggested contains every possible numerical sequence. (One thing people like to do is to find where the dates of their birthdays can be found in π’s dazzling sequence .)

The best way to celebrate this never-ending, never-static nature of π would be to try and highlight all its numbers moving along it every year.Here are the first hundred digits of π:

3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679

What I suggest is to start on 31.4. The next date π is celebrated would be 15.9 – 15th September, then26.5 26th May and so on. Π day would become just as unpredictable as π itself. Ramadan slides around the calendar, Easter and Chinese New Year wobble a bit, but I don’t there would be any celebration jumping around the calendar surprisingly like π day would do.

(Here’s a page which will tell when your birthday turns in π’s sequence: http://mypiday.com)