alt Hacker News> The moment you use a fraction, the assumption is that you would need to count all I guess, so it’s treated as individual objects.
I always explained it to myself that, when you use a fraction, you're focusing on that one incomplete object, also calling more attention to the individuality of objects in the set. So in case of say, "100.5 książki", I like to imagine shoving ~95 books into the box very quickly, then slowing down for the last 6 books, counting them off one by one, to know exactly when to stop and saw the 106th book in half.
IDK what the official justification is.
Interesting.
It's the opposite in Russian — it'd be "100½ książek" there (сто c половиной книжек), even though it's "½ książki" (половина книжки).
"½ książek" (половина книжек) is also valid, and it means "half of (all the) books".
But in "100½", it's the whole number that determines the ending (i.e. case) of the word.