"We have a million apples."
Translation:Ni havas milionon da pomoj.
You put it between quantities and items. It mirrors some use of "de" in Romance Languages, specifically use of "de" when you're not talking about possession.
For example if you want to say "I want that amount of puppies." you say "Mi volas tiom da hundidoj" and if you want five cups of tea, you say "Mi volas kvin tasojn da teo," since "tiom" indicates the quantity of "hundidoj" and "kvin tasojn" indicates the quantity of "teo". Hope this helps!
Fabiola asked why "milionajn pomojn" is wrong. Surely it is wrong because, as you said, adding an -a to a number turns from cardinal (one, two, three etc.) into ordinal (first, second, third etc). So "milionaj pomoj" would be "millionth apples", which not only doesn't mean "a million apples", it doesn't make sense (I can't think of a situation where more than one apple could be the millionth).
someone correct me if I'm wrong, but the way I think about it is this: miliono has a-o ending so it's a noun. being a noun it can become a 'container' and is treated like we learned in the da/de unit - its the container not the object in the container that gets the accusative. (also why you use da, - its holding a quantity of apples, not made for apples)
Is there some sort of pattern to the nomenclature of higher powers of a thousand, like English's "mi-llion," "bi-llion," "tri-llion," "quadri-llion? I've noticed most the ones I've learnt in Esperanto star with "mil" ("mili-ono," "mili-ardo").
EDIT: Ooooooh, is it the system where latin prefixes for
x are added to "-liono" for
1000000^x and to "-liardo" for
1000000^x * 1000?