Whether you’re great at solving math problems or just love food freebies (who doesn’t?), National Pi Day is an occasion to be celebrated. For those who need a refresher, pi is the never-ending mathematical constant. While it may feel like the year 2020 was the infinite number, the real deal begins with three digits (3.14) and is represented by the Greek symbol π. The day was officially recognized by the U.S. House of Representatives in 2009, but even before that, it’s been a popular day for celebrating round foods.