"They support both children."

Translation: Wspierają oboje dzieci.

[benny_ns]

Can someone explain when do you use "oba" and when "oboje"? It is very confusing.

[Jellei]

"Oba" is used for neuter (most of them, but not here) and masculine non-personal nouns. "Obaj" for masculine personal. "Obie" for feminine. And "oboje" before nouns denoting people of mixed sex, personal and animate neuter nouns (of which there are few), and non-masculine personal pluralia tanta.

Check this and this.

[benny_ns]

So we use "oboje" here, because "dzieci" is a mixed sex, personal and animate neuter noun in plural, right?

[Jellei]

Well, specifically personal neuter. They may both be of the same sex, we don't know.

[Soosootoo]

Thanks for this, but I've also seen 'obu' - when is that used please?

[Jellei]

You can have a look here: https://www.duolingo.com/comment/19529552$comment_id=19554885

[Soosootoo]

Oh, thanks, Jellei - so clear (and yet so difficult for me to learn!) Bardzo dziękuję!!

[tczek]

It says here oboje takes genetive, so why isn't dzieci dziecka

[DariuszKoz6]

Wspierają dwójkę dzieci?

[Jellei]

"dwójkę" doesn't mean "both", it just means "two", but maybe there are more children.