Translation:The parents ordered two books each for their three children.
I've found those sentences on Wiktionnary:
"Mi donis al la azenoj po du karotojn." "Ili ricevis po 5 pomojn."
-> why are karotojn and pomojn (with a -n ending then) ok in this sentence, and libroj has no -n ending despite being in a similar situation (ie accusative)?
I'm even more confused... =/
The way I read PIV, this means that the "karotojn" and "pomojn" are not part of the complement of the preposition "po" but are instead directly an object of "doni, ricevi", and one could more clearly write them as "Mi donis al la azenoj karotojn po du" and "Ili ricevis pomojn po 5" -- so, "I gave the donkeys carrots, two each" and "They received apples, five each".
It's possible that the person who added the sentences to Wiktionary simply made a mistake, though, and intended the meaning of "po du karotoj", "po 5 pomoj", rather than such a grammatical subtlety.
Hmmm it's still quite complicated for me, but I think that the main problem is that I'm not a native English speaker, and then that use or "each" is really confusing for me, hence the confusion about that part.
I guess I'll have to work on English first then...
Thank you for the explanation nevertheless!
Language usage about “po” is a bit controversial in Esperanto. For some, the reasoning is “ĉiuj prepozicioj per si mem postulas la nominativon” (rule 8 of the 16 basic rules), so no accusative. Others consider “po” to modify only the numeral, not the noun, which preserves the accusative it would have without “po.” Both ways are considered valid.
You could say that the sentence is analyzed either as “mendis (po du libroj)” or as “mendis (po du) librojn.”
Po isn't used in the English translation
"each" is there in the English sentence.
Your sentence most readily means that they bought two books, in total, and that the three children had to share those two books.
The English "two books each" and the Esperanto po du libroj implies that the parents bought six books: two for each child.