"There are twenty rooms in the new hotel."
Translation:V tom novém hotelu je dvacet pokojů.
Yes. it is BUT....
Tips for numbers are next to be added, so watch that space.
For now, 1 is simple, it is a singular.
2,3 and 4 are followed by nominativ. 2 pokoje, 3 pokoje, 4 pokoje
5 and everything above is followed by genitiv 5 pokojů, 6 pokojů, 18454 Pokojů.
And that translates back to agreement in number. 2, 3, 4, have to agree Tam JSOU 3 pokoje.
5 and up does not Tam JE 5 pokojů, 1000 pokojů....
You can think of the numbers beyond 4 as collective terms like "flock". The collection is singular, and what it contains is plural and expressed using the genitive, as with "a flock of birds".
Is it wrong to flip the order of the clauses here? I have "Je dvacet pokojů v tom novém hotelu" marked as incorrect.
Can you explain why? Isn't the subject of the sentence the number of rooms? Does it sound better in Czech to put the subject at the beginning of the sentence or not? I have no problem with Czech word order when things like "place" and "second position" dictate it, but with these kind of sentences I am totally lost.
The SVO order is the default, the same as in English. It can often be re-arranged and often with a change in the meaning. Some of those changes will result in quite strange things.
It is indeed possible to start with JE in sentences like "There is..." but it will sound very strange in an ordinary sentence.
Je jen jeden Bůh. There is only one God.
Jsou věci mezi nebem a zemí. There are things between Heaven and Earth.