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National Pi Day

An exciting day for math enthusiasts, celebrate this famous number — it's the ratio of the circumference of a circle to its diameter — with infinite enthusiasm and endless fun!

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Leverage the dual appeal of Pi Day to drive pie sales and STEM engagement through playful math-themed promotions and baking contests.

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  • Host a pie-baking or pie-eating contest with math-themed prizes
  • Create social media content around pi memorization challenges or math jokes
  • Partner with science museums or schools to promote educational STEM activities
  • Run in-store pie promotions tied to the 3.14 date with math-themed packaging or displays

History

The history of National Pi Day is, without a doubt, intrinsically tied to the origins of the number itself. The need for pi is as old as the wheel itself, and many techniques have been tried in many cultures to capture this elusive number in mathematics.

The reach for the whole of this number was difficult, with ancient mathematical cultures only being able to barely find out to the seventh decimal, and Indian mathematicians (some of the greatest of their time) could only manage to decipher it out to five.

Pi is truly one of the most fascinating numbers in existence, and the quest for the ultimate end of it has been sought for thousands of years.

This may tend to look like a fool’s errand, given that it seems to extend infinitely in mathematical loops beyond, and nothing has ever been found to contest this.

This is particularly remarkable when considering the following: modern techniques have been used to calculate pi out to millions of digits, and at no point has the pattern ever been found to reliably repeat itself!

The good news is that the beginning of the celebration of National Pi Day is a little more conclusive than that! Back in 1988, the Exploratorium Museum of Science, Art, and Human Perception in San Francisco was responsible for launching the first celebration of National Pi Day.

Then, in 2009, the US Congress officially recognized the day. Now, it is celebrated all throughout the world by teachers, students, mathematicians–and fans of pie!


How to celebrate

Enjoy a Pie Feast

For avid bakers, National Pi Day is the perfect opportunity to show off those pastry-making skills. Making a selection of pies at home ahead of time and bringing them to work to share would be a lovely treat. Or, even better, invite friends, family or co-workers to participate by hosting a Bake Off where pies are judged on the basis of their tastiness! If no one in the group likes to bake, store-bought pies can be just as good–and quicker. Just be sure to invite others to share in order to make it a “well-rounded” day.

Memorize Pi

Even those who aren’t avid mathematicians can memorize the Pi sequence if they put their minds to it. Although, it’s not likely a person will have enough time in their lives to name all 3.14 trillion digits that have been traced out. Even so, a catchy song with a video has been created to help budding math lovers to memorize the first 100 digits of Pi. It starts with 3.14…159…265…and so on. https://www.youtube.com/watch?v=Zb5qdtU-Mv8

Visit a Science Museum

Although the Exploratorium celebrated the inaugural National Pi Day, many science and engineering museums have now gotten on board by hosting events and activities for kids of all ages as well as adults.

Host a Pie Party

Whether wearing raincoats and throwing cream pies at each other, or winning a pie eating contest, a party that honors all things Pi(e) seems like just the right way to enjoy the Day!

Tell Some Math Jokes

Impress (and annoy!) your friends and family with these punny math jokes that will make National Pi Day even more hilarious: What’s a math teacher’s favorite dessert? Pie, of course! Why should you never ask Pi a question? Because it goes on forever. Why do teenagers travel in groups? Because they can’t even. Why are math books so depressing? Because they’re filled with problems.

Sing Happy Birthday

In addition to being National Pi Day, March 14 is also the birthday of a very important scientist: Albert Einstein. So don’t forget to sing him a little Happy Birthday song while eating a piece of pie and exploring other fun ways to celebrate the day!

Do the Math

Those falling into the more math-y side of the day might enjoy researching this number and discover all the amazing secrets it hides. Once you really get to understand the depths and complexities of it, you’ll understand why Pi day exists to celebrate a simple (and infinite) combination of digits! Since pies are round, and Pi is circumference over diameter (a number that, while being functionally infinite, also happens to be a constant in every circle ever), it only makes sense that they would both be celebrated on this day. National Pi Day (whether written 3.14 or 3/14) celebrates the long history of this fantastic number, and the long journey science has taken (and is still on) to seek the end of a number known to be infinite in length. National Pi Day Timeline1900–1600 BCE  Early Babylonian Approximations of Pi  Cuneiform tablets from Old Babylonian Mesopotamia show builders using π ≈ 25/8 (3.125) when relating a circle’s circumference to its diameter in practical calculations.   [1]1650 BCE  Egyptian Engineers Encode Pi in the Rhind Papyrus  The Rhind Mathematical Papyrus gives a method for finding the area of a circle that corresponds to π ≈ 256/81 (about 3.1605), revealing a surprisingly accurate rule used by ancient Egyptian scribes.   250 BCE  Archimedes Uses Polygons to Pin Down Pi  In his work “Measurement of a Circle,” Archimedes inscribes and circumscribes 96‑sided polygons around a circle to prove that 3 10/71 < π < 3 1/7, giving the most rigorous value of pi in antiquity.   [1]1706  William Jones Introduces the Symbol π  Welsh mathematician William Jones publishes “Synopsis Palmariorum Matheseos,” using the Greek letter π for the circle ratio, a notation later popularized by Euler and now standard worldwide.   [1]1761–1767  Pi Is Proved Irrational  Johann Heinrich Lambert showed in 1761 that π cannot be expressed as a ratio of integers, and Adrien-Marie Legendre strengthened this result in 1794, transforming the understanding of pi’s arithmetic nature.   1882  Transcendence of Pi Demonstrated  German mathematician Ferdinand von Lindemann proved that π is transcendental, meaning it is not the root of any polynomial with rational coefficients, which settles the ancient “squaring the circle” problem as impossible.   [1]1949  Electronic Computers Join the Race for Digits of Pi  Using the ENIAC computer, mathematicians compute π to 2,037 decimal places in about 70 hours, inaugurating the modern era in which ever-faster machines and new algorithms extend pi to trillions of digits.

Early Babylonian Approximations of Pi

Cuneiform tablets from Old Babylonian Mesopotamia show builders using π ≈ 25/8 (3.125) when relating a circle’s circumference to its diameter in practical calculations. [1]

Egyptian Engineers Encode Pi in the Rhind Papyrus

The Rhind Mathematical Papyrus gives a method for finding the area of a circle that corresponds to π ≈ 256/81 (about 3.1605), revealing a surprisingly accurate rule used by ancient Egyptian scribes.

Archimedes Uses Polygons to Pin Down Pi

In his work “Measurement of a Circle,” Archimedes inscribes and circumscribes 96‑sided polygons around a circle to prove that 3 10/71 < π < 3 1/7, giving the most rigorous value of pi in antiquity. [1]

William Jones Introduces the Symbol π

Welsh mathematician William Jones publishes “Synopsis Palmariorum Matheseos,” using the Greek letter π for the circle ratio, a notation later popularized by Euler and now standard worldwide. [1]

Pi Is Proved Irrational

Johann Heinrich Lambert showed in 1761 that π cannot be expressed as a ratio of integers, and Adrien-Marie Legendre strengthened this result in 1794, transforming the understanding of pi’s arithmetic nature.

Transcendence of Pi Demonstrated

German mathematician Ferdinand von Lindemann proved that π is transcendental, meaning it is not the root of any polynomial with rational coefficients, which settles the ancient “squaring the circle” problem as impossible. [1]

Electronic Computers Join the Race for Digits of Pi

Using the ENIAC computer, mathematicians compute π to 2,037 decimal places in about 70 hours, inaugurating the modern era in which ever-faster machines and new algorithms extend pi to trillions of digits.


FAQ
How did the Indiana Pi Bill of 1897 propose to change the value of pi?
In 1897, Indiana’s legislature considered a bill to redefine pi as 3.2. An amateur mathematician claimed to have squared the circle, a mathematical impossibility. The bill passed the House but failed in the Senate, preserving pi’s true value.
Why do some mathematicians advocate for Tau Day over Pi Day?
Tau equals 2π, approximately 6.28. Advocates argue it’s more intuitive for circle calculations. They celebrate Tau Day on June 28 (6/28).
What is the connection between Pi Day and Albert Einstein?
Albert Einstein was born on March 14, 1879. Princeton, New Jersey, honors both Pi Day and Einstein’s birthday with events like look-alike contests and lectures.
How did the “Pi in the Sky” project combine art and mathematics?
In 2012, artist ISHKY used skywriting planes to write 1,000 digits of pi over the San Francisco Bay Area. The project merged art and math, creating a temporary, large-scale visualization of pi.
What is the significance of the “Pi Pie” tradition?
Bakers create pies with the pi symbol or digits on top. This tradition combines culinary art with mathematical celebration, making math more approachable.
How did the “Pi Day of the Century” in 2015 differ from other Pi Days?
On March 14, 2015, at 9:26:53 AM, the date and time represented the first ten digits of pi (3.141592653). This alignment occurs once per century, making it a unique celebration.
What is the “Pi Chain” world record?
In 2017, students in Todi, Italy, created a human chain of 520 people, each holding a digit of pi. This set a Guinness World Record for the longest human representation of pi’s digits.
How is Pi Day celebrated in different countries?
In Japan, math enthusiasts recite pi’s digits. In the UK, schools hold pie-eating contests. In Canada, math teachers organize pi recitation competitions. These diverse activities reflect cultural approaches to math education.
What is the “Pi-Ku” poetry form?
A “Pi-Ku” is a poem with syllable counts matching pi’s digits: three syllables in the first line, one in the second, and four in the third. This creative form blends poetry with mathematics.
How did the “Pi Day Anthem” become part of the celebration?
In 2015, musician John Sims released the “Pi Day Anthem,” a rap song celebrating pi. The song gained popularity, adding a musical element to Pi Day festivities.