SAN FRANCISCO -- Every March 14, mathematicians, scientists and math lovers around the world celebrate Pi Day, a commemoration of the mathematical sign Pi. That's because the date written numerically ...

Originally defined as the ratio between the circumference of a circle and its diameter, pi — written as the Greek letter π — ...

For more than a century, Srinivasa Ramanujan’s uncanny formulas for the number pi have looked like pure mathematical ...