Tomorrow is March 14, or 3/14. That means it’s time to celebrate Pi Day! Pi, represented with the Greek letter π, is a mathematical term for the ratio of a circle’s circumference to its diameter. It is used in geometry, physics, and engineering. Although Pi is actually an infinite decimal, the first three digits of the number are 3.14, which is why we celebrate Pi on March 14.

Are you planning to celebrate Pi Day? You could eat a slice of pie! Get more ideas for Pi Day activities on the Exploratorium website.