Add Yahoo as a preferred source to see more of our stories on Google. Imaginary numbers push the boundaries of calculus and other branches of math. Hill Street Studios/DigitalVision via Getty Images ...

Today is Cinco de Mayo. And this year, the fifth of May is filled with mathematical joy. It is — Square Root Day! It all started in 1981. "I was writing a check in late August," says Ron Gordon, who ...

To a nonmathematician, having the letter “i” represent a number that does not quite exist and is “imaginary” can be hard to ...