Today's date is March 14, 2015. That's 3/14/15. That's the first five digits of pi! And if you're using 12-hour time, then you have two chances to be reading this at 9:26:53. That's the first ten digits of pi! Oh happy day!

And a welcome chance to stick a thumb in the eye of all those buzzkills who would prefer we celebrate tau day instead.

Since pi is an infinite, nonrepeating decimal whose digits, so far as anyone can tell, are statistically random, we might wonder if every ten-digit sequence of digits appears somewhere in its decimal expansion. If the answer is yes, then any combination of date and time can be thought of as pi day (until we get to October 10, of course, when we would need to start looking at eleven-digit sequences.) It is known that most real numbers are normal, meaning that every finite sequence of digits of a given length appears with the same frequency as every other sequence of the same length. This would imply that every finite sequence of digits appears somewhere in the decimal expansion of a normal number. Alas, it is not known if pi is among the “most,” or is instead one of the exceptions.

As it happens, a few years back I wrote a post for the Oxford University Press blog on the subject of pi. So go have a look!

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"Today’s date is March 15, 2015. That’s 3/14/15."

Now that is an unfortunate typo!

Oops! Transatlantic numerical coding systems come unstuck again. Pi day would actually be the 31st April 2015, if only April had consented to receive a full allocation of 31 days in the first place! Also, we will need to omit the”0” from the “04 ” normally used to signify the fourth month in a system where 2 digits are generally employed to register month progression – a total of 2 digits being the maximum number that can possibly be required to indicate any of 12 possibilities.

If we are trying to systematise a quantity which requires numerical expression of 3 successive increments of different orders, then it seems to me that we have 2 logical choices:-

1)We can start with the smallest order (day), then proceed to indicate the medium size order (month), and then place the year numerator, as the largest, in 3rd place. This would give us 14th March 2015 as 14.3.15 (or 14.03.15).

or

2)If we really insist, then I suppose we could reverse the above order, and go from largest to smallest – 15.3.14 (or 15.03.14).

The only options that are clearly excluded by the rules of common sense and logic are those which insist on placing the middle order quantity at either end, first or last.

Can anyone explain to me how you Americans managed to come up with such a bizarre way to express the date? I’m sure you can’t have got it from anyone over this side of the pond, so someone over there must have dreamed it up somehow, and then succeeded in persuading his compatriots that such an anomalous system should be generally adopted. Was it perhaps done along similar lines, and perhaps for similar political reasons, as your early 19th century decision to start spelling lots of words incorrectly as well?

Heh! Thanks for pointing out the typo, which has now been corrected.

A friend sent me an article detailing some of the PI DAY goings on in her town. This is one of them.

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So much for entering codes on a phone in the woods while walking a dog

Meh. I prefer 22 July as Pi day, ie 22/7 written in the usual order in Europe. Also, it is not so dependent on the decimal system as the approximation 3.14.

I can't help but think that treating this year's pi day as special is a bit of a cheat because of the fact that the year has to be abbreviated to two digits to make it work. The REAL pi day would have occurred on March 14, 1589 (3/14/1589). Wonder if anyone noticed.

I saw a poster of pi day in our Math Building and I was rather amused by it. To my dismay, my friend who was with me at that time didn't seem to 'get' it. It got me thinking that math jokes, riddles and other fun stuff isn't really accepted by a majority of the population. Oh well! Let the mathematicians forever be called Nerds! I know I don't mind!