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,

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.