No, not pie 🥧…Pi Ï€. What is Pi Day? The numbers for the date 3/14 match the first three digits of the mathematical constant Pi. Divide a circle’s circumference by its diameter; the answer is always approximately 3.14. Check out Pi Day activities at the Exploratorium — which founded Pi Day in 1988. https://www.exploratorium.edu/pi?gclid=Cj0KCQiAnKeCBhDPARIsAFDTLTLvpTQ3336WAYczx-OiIi2aViZaLmfAilw8_U6DZNTC2boj7u-HPZ4aAg1TEALw_wcB