nott: Dziewięcioro is a normal numeral.
'Dziewięcioro" is a collective numeral [the so-called 'liczebnik zbiorowy' in Polish]; a 'normal' numeral would be 'dziewięć'.
Is it? Why don't we use normal numerals with kids, then?
How much is it now to Burma...
Generally, we may say that the problem of the Polish collective numeral is gramatically very complex and difficult.
Nah, there must be some legit rule....
As has been shown in this thread, native speakers are confused and may change their opinions on them.
Because nobody counts hundreds of children with this accuracy! Who'd bloody care...
Shall I remind that the whole discussion had started with Nott's wrong assumption of the case of the noun which accompanies the collective numeral used in the instrumental:
nott: Ze stu dziewięćdziesięciorgiem dziewięciorgiem dziećmi. Dziećmi, not dzieci.
Yeah, right. Just point at poor nott. I was trying to be helpful...
Sigh... right, it is confusing. You need to study it to get it right. I don't have to, I am Polish born and bred, my Polish is nigh to perfect. And if not, then it's a native error, possibly a norm in the near future. And during my whole life in Poland and I never had an opportunity to say anything like 'I was strolling with 192 kids.'
Bottom line, then... it's a rather artificial problem. Unless you keep to practical numbers, like dziewięcioro.
Edit:
Thanks for the inspiration, though.