Zero is a tricky number. It's the only integer that is neither positive nor negative. You cannot divide by zero, but you can add, multiply, and subtract. It is simultaneously a number (in the sense of an integer) and the absence of a quantity (in the sense of "none"). So how did we get zero, and why is it so odd unusual?

In the short animation below, Dr. Hannah Fry explains the story of zero. It's a number with ancient origins and worldwide implications. Enjoy:

If you're not into video, Wolfram Mathworld explains the math aspects of zero very well (minus the history bits), and this Yale Global article handles the history. (You might also consider that zero can be a hero.)