National Pie Day was January 23. But if you missed it, you can still have a slice of pie to celebrate the other kind of Pi Day, which is on March 14.

Pi Day is when math enthusiasts celebrate the mathematical wonder that is pi by talking about it all day long. We’ll let the geeks have their say — as long as they serve pie.

*Warning: this article contains math.

 Pi to the Rescue

What is pi, anyway? Pi (pronounced like “pie”) is a symbol used to represent the ratio of a circle’s circumference to its diameter. In order to understand this properly, you’re going to have to let me give you a basic math lesson. It’ll be quick, I promise. And hopefully painless, too.

Okay, here goes:

I have a circle and I want to know what the value of the circumference is. How on earth do I figure that out? Pi to the rescue! And a simple equation that goes C=2πr. (C is circumference, r is radius.) I measure the radius; it’s 3.5 inches, I get out my trusty scientific calculator and presto, I’m a genius.

C = 2π7 so C = 21.99

The great thing about pi is that it is a mathematical constant, which means that it works the same way for all circles, no matter the size. Also, it’s an irrational number, which means that the digits go on forever without any pattern. There are loads of other circle-related equations that use pi. Basically, if it’s a circle or a circular kind of shape like a cylinder, then pi will be involved.

 To Infinity and Beyond

Pi is way cooler than you think. It goes on forever. And ever. Maybe that’s why math geeks love it so much — it’s a challenge than can never be completely solved, or the gift that keeps on giving.

Want to know the numerical value of pi? Are you sure?

Take the circle we used above. Divide the circumference by the diameter. All you math whizzes do this sum in your head. Everybody else join me in using a calculator.

π = C/d

π = 22/7 so π = 3.14

And now you can see why Pi Day is on March 14! Because March 14 is also 3/14. 2015 was an especially great year for pi fans, because the next two digits of pi are actually 3.1415!

Yup — 3.14 is pi for dummies. Really it’s 3.14159265359 and on and on and on. Because it’s infinite, there is no end to the decimal places that you can calculate.

 22 Trillion Digits and Counting

Since we’re going on and on about the infiniteness of pi, I bet you’re wondering just how many digits of pi have been calculated so far. In November 2016, one pi enthusiast broke the world record for calculating pi to more than 22.4 trillion digits.

(Excerpted from Mishpacha Jr., Issue 751)