This Pi Day, how to BAKE pi(e) — and have mathematical fun. March 14, 2023 12:10 AM ET. By . Emily Kwong , Berly McCoy , Rebecca Ramirez , Gisele Grayson ...

March 14 is celebrated as Pi Day because the date, when written as 3/14, matches the start of the decimal expansion 3.14159… of the most famous mathematical constant.

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.