Arithmetic of rational numbers (Math 0)

Now that we’ve seen what the ra­tio­nal num­bers are, we’ll move on to work­ing out how to com­bine them.

There are four main ways to com­bine ra­tio­nal num­bers, and col­lec­tively they are called “ar­ith­metic”:

Ad­di­tion­ally, we can com­pare ra­tio­nal num­bers with each other; and we can show that all of these op­er­a­tions play nicely to­gether in a cer­tain sense.

This page is the start of an arc which will go through all of these ideas. In the pro­cess, we’ll get you fa­mil­iar with the no­ta­tion that we use for ra­tio­nal num­bers; it’s a very con­ve­nient short­hand once you’ve learnt the con­ven­tions.