God created the real numbers

A friend of mine argued that "math is invented" rather than discovered. This seemed wrong to me and in arguing against it I found https://plato.stanford.edu/entries/nominalism-mathematics/

At least at this stage I think it relates to whether you believe "the universe"/reality is a sort of momentary collection of the currently-existing things. Vs seeing reality as the set of all things that might obstruct "me" or any entity from doing something.

To me, even if the wall is invisible it's still a wall

I personally consider it invented. The universe is what it is. Math is a model we've collectively built that tries to work within the underlying rules of how logic works in the universe. Like all models, any disagreement with observation means our model is wrong.

But honestly, the whole question is akin to asking how many angels can dance on the head of a pin.

On a separate subject, that site you linked does something strange with scrolling on Firefox mobile. Hey web devs - stop screwing around with things like scrolling! Browser devs implement scrolling in a consistent manner. You aren't making the user experience better with your silly JavaScript tricks!