A Slice of History: The Delicious Origins of Pi Day
Every March 14th, math teachers everywhere rejoice, math students get curious (and sometimes confused), and bakeries mysteriously sell more dessert than usual. That’s right—we're talking about Pi Day, the one magical day a year when math and dessert collide in glorious harmony.
But where did Pi Day come from? Why is it celebrated on March 14th? And why do we associate one of the most irrational numbers in mathematics with delicious, circular pastries?
Let’s roll back the clock and take a bite out of the history of Pi Day. 🥧
What’s the Big Deal About π?
Before we dive into parties and pies, let’s not forget the main character of the day: pi, or the Greek letter π, which represents the mathematical constant approximately equal to 3.14. It’s the ratio of the circumference of a circle to its diameter, and it goes on forever without repeating—just like a middle schooler’s story about lunchroom drama.
The symbol π was first used in the 1700s by Welsh mathematician William Jones, but the concept itself has been known for thousands of years. Ancient Babylonians and Egyptians were calculating early versions of pi long before calculators (or pie plates) existed.
Why March 14th?
Well, 3/14 just happens to line up with the first three digits of pi: 3.14. Throw in the fact that it’s also Albert Einstein’s birthday, and you’ve got yourself a mathemagical double feature!
In 1988, Larry Shaw, a physicist at the San Francisco Exploratorium, decided pi needed a party. He and his fellow math nerds marched in a circle and ate fruit pies to celebrate the never-ending number. Thus, Pi Day was born.
In 2009, the U.S. House of Representatives got in on the fun and officially recognized March 14th as National Pi Day. Yes, Congress actually passed something... about math. 🤯
What Do Math Teachers Do on Pi Day?
If you’re new to Pi Day, here are just a few traditions teachers love to circle back to every year:
Pie Eating Contests 🥧 – A perfect excuse to break out the whipped cream.
Pi Digit Memorization Challenges – That one student who can recite 54 digits of pi from memory? Let them shine!
Pi Crafts & Art Projects – Create a pi skyline or color a pi spiral with colored pencils.
Circle Measurements Galore – All the area and circumference activities your heart desires.
Pi-themed Riddles and Puns – Because who doesn’t want to hear, “I 8 sum pi,” at least ten times? Some of you may have that shirt…
Weird but Wonderful Pi Facts
Pi has been calculated to over 62 trillion digits… but you only need about 39 digits to calculate the circumference of the observable universe with extreme accuracy. The rest? Just gravy. Or whipped cream.
March 14, 2015, at 9:26:53 AM, was the ultimate Pi Day moment: 3.141592653.
Some math enthusiasts celebrate “Tau Day” on 6/28 because tau (τ) is equal to 2π. But let’s not start a math fight.
Why Pi Day Matters (Even If You’re Not Into Dessert)
For students, Pi Day is a reminder that math can be fun, weird, and celebrated. It’s a chance to step outside of the textbook, get a little goofy, and build memories that stick long after the lesson is over.
It’s also a great time to dig into circles, irrational numbers, and even math history—all wrapped in a package of whipped cream, classroom games, and laughter.
Ready for a Pi Day Activity?
If you're looking to make this year’s Pi Day celebration unforgettable, check out our Circle Coloring Worksheet:
🎉 Area and Circumference Fun:
25 questions on area of circles
25 questions on circumference of circles
Great mix of radius and diameter practice
Diagrams and a mystery picture that students reveal as they work!
🖍️ Perfect for Pi Day or anytime you're teaching circles
✅ Easy-to-grade and self-correcting
🖨️ Printable PDF, two-sided with a key
👉 Download it today and make your Pi Day both meaningful and memorable!
So whether you’re a math teacher, a pie lover, or both, Pi Day is a celebration of the infinite, the irrational, and the wonderfully nerdy side of learning. Now go grab a slice—of learning, of pie, or both—and let’s hear it for 3.1415926535...
Happy Pi Day from Mr. Slope Guy! 🥧
