Originally defined as the ratio between the circumference of a circle and its diameter, pi — written as the Greek letter π — appears throughout mathematics, including in areas that are completely ...

Irrational numbers are numbers that cannot be expressed as the ratio of two whole numbers. This is opposed to rational numbers, like 2, 7, one-fifth and -13/9, which can be, and are, expressed as the ...

This Pi Day, as you’re enjoying your slice of pie, explore a bigger slice of mathematics. Most March 14 celebrations are obsessed with the number pi. If you think “obsessed” is too strong, take a look ...