Pi Day is celebrated on March 14 (3/14) around the world. Pi (Greek letter “π”) is the symbol used in math represent a constant — the ratio of the circumference of a circle to its diameter — which is approximately 3.14159. Fifth-grader Liberty Sprain at Coulee Montessori can recite 50 digits of Pi in the correct order from memory because of a song she wrote. Happy Pi Day! | School District of La Crosse