So you learned about zero as a concept. The first thing people tell you, when they tell you about zero itself, is that division by zero is "undefined".

But why ?

Consider this:

You divide 1 by some small thing, like 0.1. Results in 10. Np.

You divide 1 by some smaller thing, like 0.001. Results in 1000. Np.

But

You divide -1 by some small thing, like 0.1, Result is -10 (wtf?)

You divide -1 by some smaller thing, like 0.001, Result is -1000. (Hell...)

So we can conclude division by zero is undefined (inside the field of real numbers, of course there are some tricks up a complex sleeve... hehe) for the following, simple reasoning:

When dividing anything by "something" small, the result strongly depends on the sign of the numbers put in as a dividend beforehand.

Clearly, something big doesn't equal something exactly as big with a negative sign,

We don't do this kind of bs. As long as we want to stay real.

That is why it is "undefined", in most contexts.