“Pi Day” was celebrated in many countries on March 14. Pi (Greek letter “π”) is the name of a constant number in mathematics that represents the relationship between a circle’s diameter (its width) and its circumference (the distance around the circle). The value of the number is 3.1415926535… (and its digits go on forever).

Since March 14 is written as 3/14 in some countries, this day is celebrated as Pi Day. Many people eat and gift food in the shape of a circle (pizza and pies) to celebrate the number. Albert Einstein, one of the world’s greatest scientists, was born on Pi Day. The mirror image of “3.14” spells “PIE”. Some nations where the date is written as day/month celebrate Pi Approximation Day on July 22. This is because the fraction 22/7 is used as an approximation of pi.

In November 2016, over 22.4 trillion digits of pi were calculated. Here is a video about it, and another about pi.

### Did you know?

The first 144 digits of pi add up to 666, and 144 = (6+6) x (6+6).

*Image Credits: https://en.wikipedia.org for the circle image, RR Auction and Einstein’s World Author for Einstein’s image*

*Sources: www.piday.org, https://www.timeanddate.com, https://www.newscientist.com, SciShow*