Think of a fraction as a pizza. The bottom number is how many slices the pizza has, and the top number is the slices that you are going to eat. Sally will eat the rest, so you need to leave some for her.

In the beginning... there was nothing...

A plane is just a burrito.

And monads are like burritos. Therefore, monads are like planes. How shall we represent diverted luggage?

I know it's a tradition to bash Americans, but I'm quite sure in any country, Ax + By + Cz + D = 0 is a plane isn't common sense.

I learned it in the mandatory part of school (I'm French) so while I'm sure lots of people have forgotten it, most did learn it at school..