What's the coolest mathematical fact that you know?

@daisymay Yeah, I've been puzzled about that, since I first heard it in high school. Could someone please explain "raising a number to the power of zero," the way "x to the power of y" can be explained as "x multiplied by itself y number of times"? Or is to the "power of zero" just an absurdity no one worries about, for the convenience of certain calculations, the way imaginary numbers have been conceived? (unless I'm mistaken about those too)?

I used to know the explanation, but that was about 35 years ago :D