March 14 — a day you’re more likely than most others to eat — or throw — a pie and get a reduced price on your pizza. It’s all in celebration of pi (Greek letter π), the mathematical constant and infinite number whose first three digits are 3.14.

Math enthusiasts around the world, from college students to rocket scientists, celebrate Pi Day, which is March 14 or 3/14 — the first three digits of an infinite number with many practical uses. Many people will mark the day with a slice of pie — sweet,