"It is a quarter past twelve."
Translation:Je čtvrt na jednu.
I had forgotten that jedna itself was gendered (though only numbers one and two are gendered, if I understand correctly). Sorry - coming from a non-gendered language, it always takes a while for these things to drop in fully. Thanks for your clarification on both questions.
...reading this discussion has actually confused me a little bit. My understanding was that "jeden" is basically treated as an adjective, so in this case, "jedna" actually is referring to "jedna hodina." It's the word hodina that has a fixed gender, not jedna itself. (Mods, please correct me if I'm wrong!)