Add Yahoo as a preferred source to see more of our stories on Google. Celebrate Pi Day and read about how this number pops up across math and science on our special Pi Day page. For more than two ...

Most people first learn about the number π (pi) in school, usually when studying circles. It is often written as 3.14, but this is just an approximation. In reality, pi is an irrational number, ...

This day only comes 'round' once every year! Today is Pi Day for 2026, the universal celebration of an amazing, mysterious, and irrational mathematical constant. What's that, you say? Why do we ...

The holiday was created in 1988 by Larry Shaw, a physicist at the Exploratorium science museum in San Francisco.