That's a tautology, you can similarly say "imagine a world where mathematics isn't tied to the real or fictional existence, in this world mathematics isn't tied to the real or fictional existence".

>And on the second point, by assuming 0/0=1, either you have left the realm of natural numbers (or real numbers), or you have to break the distributive law of addition, or all the symbols mean completely different things.

I didn't do such things.

> Otherwise, you are essentially declaring both 1!=2 and 1=2, which is not math.

It's derived from initial assumptions, which is how all math works.