https://en.wikipedia.org/wiki/Continuum_hypothesis

Hmm. Frankly speaking I always assumed Mathematicians had more of an idea about infinities I mean why even have indices if you don't have an inductive rule to descr... oh wait never mind.

That said the reals aren't countable yet we have perfectly reasonable ways to deal with them symbolically, even compute with them, represent ~~every single one of~~^1^ them in finite space, it's just when you want to compare or output them with infinite precision that you might have to wait for eternity. But who needs infinite precision anyway, arbitrary precision is plenty.

^1^ On second thought, after diagonalisation, no we don't. Or we do because there's some magic going on with included transcendental constants that break through that do I look like a numerologist.