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14 March 2011

Happy Pi Day! Eat an apple Pi! Recite 22,514 digits of the decimal expansion of Pi!

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Today's also Albert Einstein's birthday.


Pi Day is a holiday commemorating the mathematical constant π (pi). Pi Day is celebrated on March 14 (or 3/14 in month/day date format), since 3, 1 and 4 are the three most significant digits of π in the decimal form. In 2009, the United States House of Representatives supported the designation of Pi Day.[2]

Pi Approximation Day is held on July 22 (or 22/7 in day/month date format), since the fraction 22⁄7 is a common approximation of π.[3] This date is also referred to as "European Pi Appreciation Day" because of the European practice of placing the day before the month.


Larry Shaw created Pi Day in 1989.[4] The holiday was celebrated at the San Francisco Exploratorium, where Shaw worked as a physicist,[5] with staff and public marching around one of its circular spaces, then consuming fruit pies.[6] The Exploratorium continues to hold Pi Day celebrations.[7]

On Pi Day 2004, Daniel Tammet recited 22,514 decimal digits of π.[8]

On March 12, 2009, the U.S. House of Representatives passed a non-binding resolution (HRES 224),[2] recognizing March 14, 2009, as National Pi Day.[9]

For Pi Day 2010, Google presented a Google Doodle celebrating the holiday, with the word Google laid over images of circles and pi symbols.[10]

Date Abstractions from Pi

Pi Day is observed on March 14 because of the date's representation as 3/14 in month/day date format. This representation adheres to the commonly used approximation of 3.14 for π.

The fractional approximation of π = 22⁄7 resembles the date July 22 in the day/month format, where it is written 22/7. Pi Approximation Day is therefore celebrated on July 22.

In 2015, Pi Day will reflect five digits of π (3.1415) as 3/14/15 in month/day/year date format.


There are many ways of celebrating Pi Day. Some of them include eating pie (pi and pie being homophones) and discussing the relevance of π.[1]

The Massachusetts Institute of Technology often mails its application decision letters to prospective students for delivery on Pi Day.[11]


transex roma said...

This can't work in reality, that is exactly what I suppose.

muebles coslada said...

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