"Il traduit un livre russe de deux mille pages !"

Translation: He's translating a two-thousand-page Russian book!

[KristianKp]

Russian might just as well be before the number in English. I really don't like how Duo is picky about the language that's not being taught.

[b_adger]

In particular, since the emphasis is on the large number of pages in the book, "He is translating a Russian book with two thousand pages" is probably better.

[effyleven]

I would say, "... of two thousand pages.".. but that is being super-picky.

[CarolineDa134133]

It's accepted

[TimmyKilminster]

I'm guessing you're not a native speaker, KristianKp! "A Russian two-thousand-page book" sounds very odd.

Here's a helpful source: https://www.perfect-english-grammar.com/order-of-adjectives.html

[MandyB11]

"He is translating a Russian book of 2000 pages" accepted (including the digits. Don't do that in French though. 1-10 usually are ok, but I don't take chances after that!)

[effyleven]

"He is translating a Russian book of two thousand pages."
Accepted, 5 Aug 2021

[IllparlerFrench]

I'm very confused when using « à » vs « de » when describing something. Previous lessons use « à » while here we use « de » to describe the Russian book.

[effyleven]

"He is translating a Russian book of two thousand pages."
Accepted. 6 August 2021.

[Martyn413385]

This "translation" is a great example of introducing an abominable adjectival noun! A straightforward literal translation is all that is required here - as suggested by many others previously.

[effyleven]

"Russian" SHOULD go before "number of pages," just as it does in French.
Reported!