"I eat half an apple for breakfast."

Translation: Jem pół jabłka na śniadanie.

[benulo]

That's not enough to last until lunch time

[immery]

maybe they mean second breakfast that has to last from early morning breakfast till Polish "obiad" at 3 pm.

[TatsHir]

why not "pół jabłko" for "half an apple"?

[Jellei]

Think of it as "a half of an apple". "of" means that Genitive is needed.

[TatsHir]

Thank you very much. Your comments are always very helpful!

[Popo-lsku]

"Jem połowa jabłka na śniadanie." should also be ok!? Heeeelpp.....

[Jellei]

It's close, but you used "połowa" in Nominative, although it should be in Accusative, as needed by "jeść". "Jem połowę jabłka na śniadanie".

With something relatively small, like an apple, the diminutive form "połówka" (Jem połówkę jabłka) sounds better to me, but it doesn't mean that "połowa" is wrong.