Translation:Two divided by zero? That is impossible.
This phrase is short for "Kettőben a nulla hányszor van meg?" or something similar. (You could also say "Kettő osztva nullával.") "Háromból kettő" (3-2) is "Háromból kettő elvéve/kivonva."
There are just some usual phrases that you can leave parts out from because they're still understood. This is one of them.
English speakers think of division as "x divided by y" means "y into x." How many times does y go into x? Maybe Hungarians just think of it as "y in x"? Remember, these are people who go "onto" airports and "think on" things, right? :) Just teasing - I'm sure Hungarians think English speakers have an odd use of prepositions, too. But that's why you can't translate the prepositions/case endings/whatever you want to call them literally.