There are many fun and innovative ways to celebrate Pi Day in your classroom and beyond—you probably already use it as a jumping-off point for key mathematical lessons. If you're in need of something to invigorate your tried-and-true Pi Day traditions, NCTM has you covered!

Pi Day is on March 14, and any day that combines fun, education, and pie is a day worth celebrating! Pi, also known by the Greek letter “π,” is a constant value used in math that represents the ratio of a circumference of a circle to its diameter, which is just about 3.14….15…9265359… (and so on). Not only that, but the fourteenth of March is also Albert Einstein’s birthday, so all together it’s nothing short of a mathematician’s delight.

Top 25 Most Interesting Pi Facts. Pi is the most studied number in mathematics, and for good reason. The number pi is integral to our understanding of geometry. Pi has uses in physics, astronomy, and mathematics. Pi is used in architecture and construction as well, and has been a vital part of everything from arches and bridges to the Pyramids of Giza.

No number has captured the attention and imagination of number fanatics and nerds throughout the ages as much as the ratio of a circle's circumference to its diameter--a.k.a. pi. With incisive historical insight and a refreshing sense of humor, The Joy of Pi brings us the story of pi and humankind's fascination with it, from Archimedes to da Vinci to the modern day Chudnovsky brothers, who holed up in their Manhattan apartment with a homemade supercomputer churning out digits of pi into the billions.

LucyTuning is a musical microtuning system derived from Pi and the writings of John "Longitude" Harrison. This system enables users to modulate and transpose using any scales or keys that they may choose.

Learn about pi and the history of Pi Day before exploring some of the ways the number is used at NASA. Then, try the math for yourself in Pi Day Challenge.