Friday is Pi Day, a national celebration of the mathematical concept, which is the ratio of a circle's circumference to its diameter and equals 3.14... Schools and museums often plan events to celebrate the concept, which has fascinated humans for centuries, and local eateries offer pie-related deals.

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.

It's Friday, March 14 —3/14, the day that every math nerd eagerly anticipates each year. Known around the world as "Pi Day."

WEST PALM BEACH, Fla. (AP) — 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, savory or even pizza.

Pi Day is a favorite holiday for both food lovers and mathematicians. For the foodies, the reasoning is simple. Pi Day brings discounts and deals for people looking to grab a pizza to celebrate the holiday.

Pi, defined as the ratio between the circumference of a circle and its diameter, is what's known as an irrational number. Despite its ubiquity, not only across math but also in fields as varied as medicine,