The ancient Greeks wanted to believe that the universe could be described in its entirety using only whole numbers and the ratios between them — fractions, or what we now call rational numbers. But ...

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

Math lovers celebrate March 14 as Pi Day, in honor of the irrational number pi. Pi, or π, is defined as the ratio of the circumference of a circle to its diameter. Pi is an irrational number, meaning ...