This is part of the game explained in -? wiki?.
By reaching this part, you can read this little hint (probably the only one), about why the game has such weird name: It is an auto explained adaptation, through logic.
A good way to understand it might require a deep study of characters origin, and some abstraction of what we are used to see. Where letters, numbers, alphabets came from? It's obviously all related somehow. Also most terms used in basic mathematics are usually defined out of the language and then adopted by it, such as "summing" or "dividing". Keep in mind the whole context of the game, since the beginning.