I think I have found the ultimate question to the universe itself.

[Adonai One]

Infinity - Infinity = Infinity

It seems all one needs to know is basic math.

Ankh, thank you for making things very clear.

Actually, with the knowledge of basic math, you get to learn that we really have no way of mathematically working with the concept of infinity in a natural way.

So what we do is that we introduce the CONCEPT of infinity, in such a way that:

You take the already existing structure "R" (real numbers), and you call the new structure "R+". (Expanded R). Now, R+ contains +inf and -inf, for which you need to define the following:

For all x in R:

x + inf = inf
x + (-inf) = (-inf)
(-inf) < x < inf
x/inf = 0 = x/-inf

The inf + (-inf) is not defined, it cant be done in math.

In paper-based math, yes. In physics, undefined is always infinity.