"She has two thousand books."

Translation: Ela tem dois mil livros.

[SeaOfSand]

Hmmm. In another example "de" was added - e.g. "tenho um milhão de amigos"- so i tried it here just to check but "Ela tem dois mil de livros" was not accepted.
Is this because "de" is used as in "millions of friends" i.e. some imaginary number?

[Paulenrique]

It is the use of the verb querer. "You want a million OF what?" "Quero dois milhões de amigos", and "tenho dois milhões de livros". Davu had posted a very interesting point, but he deleted :( he posted, as you have received on your email, that it's necessary to use DE after million, billion, etc.

[SeaOfSand]

Yes, I read the email. Nice to know. Duolingo could have made that clearer :)

[LinguDemo]

Does she own a library?!

[PabloB.1]

Hi,

I would question her: have you read all of them?

[MariaSilfverberg]

Why is mil accepted ? Should it be dois milhoes when plural?

[Davu]

"Milhões" is millions not thousands. "Dois mil" is correct: http://pt.wikipedia.org/wiki/Dois_mil

[salgadomarcelo]

2000 esta correto

[Luis_Domingos]

O Duolingo encoraja os seus usuários a escrever os números por extenso para poderem aprender e treinar a escrita dos mesmos (o principal objetivo de uma frase como essa).

[Summer2265]

why not ' dois mils"

[Luis_Domingos]

That's just not how it's done with "mil". Only the number that gives you the thousands changes (dois mil, três mil, quatro mil, dezessete mil, noventa mil, etc.).

[ISpeakAlien]

Do you say "two thousands" in English? Also the plural of mil is milhares.

[deactivated user]

I should probably know this by now but can "estar com" and "ter" be used interchangeably?

e.g. Ela está com dois mil livros. = Ela tem dois mil livros.

[Paulenrique]

"está com" could hase a sense of a temporary action in this case.

[deactivated user]

So if I understand correctly, it could be used in this case if she MOMENTARILY has 2000 books?