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,

Today is March 14th, celebrated as National Pi Day. This day honors the mathematical constant 3.14, which represents the ratio of a circle's circumference to its diameter.

First Slice Pie Café in Chicago is offering a Pi Day deal at their Montrose, Manor and Andersonville locations. They’re offering slices of pie for $3.14, mini pies for $6.28 and whole pies for 20% off. Those who are in the store at 3:14 p.m. will also receive an "exclusive surprise," according to the shop's Instagram post.

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 Day is Friday, March 14. Restaurants like Blaze Pizza, Sauce, Papa Johns will offer pizza deals, while Village Inn and others will have pie deals.

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,