Кадастровый номер земельного участка указали в документе.

Because it depends on номер.

Russian often uses the pattern X чего? = the X of what? So:

• номер = number
• номер земельного участка = the number of the land plot

That is why земельный участок changes to земельного участка:

• земельный → земельного
• участок → участка

Both words are genitive singular, and the adjective agrees with the noun.

No. It is the direct object.

A very common source of confusion is that номер looks like a nominative subject form. But here it is actually accusative singular. For inanimate masculine nouns, the accusative often has the same form as the nominative.

So:

• кадастровый номер can be nominative or accusative
• in this sentence, it is accusative because it is what was indicated

The verb указали does not agree with this noun phrase as a subject. Instead, the subject is left unstated.

This is a very common Russian pattern called an indefinite-personal construction.

Указали literally means they indicated, but Russian often uses 3rd person plural with no explicit subject when the speaker means:

• someone
• people
• the officials
• they
• somebody

So the sentence does not necessarily mean a specific group of people already mentioned. It often means something like:

• They indicated the cadastral number in the document
• The cadastral number was indicated in the document

It is a natural way in Russian to leave the agent vague or unimportant.

Because указали is perfective, and it presents the action as completed.

Here the idea is that the number was entered or stated as a finished fact. That is why указали fits well.

Compare:

• указали = they indicated it, they put it in, they stated it as a completed action
• указывали = they were indicating it / used to indicate it / indicated it repeatedly / were in the process of indicating it

In a sentence like this, especially in administrative or legal language, the perfective form is very natural because it focuses on the result.

Because в документе expresses location: the information is in the document.

With в, Russian usually works like this:

• в + accusative = motion into something
• в + prepositional = location inside something

So:

• в документ would suggest movement into a document, which is not the idea here
• в документе means the number appears inside the document

That is why документе is in the prepositional case.

Yes. Russian word order is much more flexible than English word order.

This sentence begins with Кадастровый номер земельного участка, which puts that information first. Other word orders are possible, for example:

• В документе указали кадастровый номер земельного участка
• Кадастровый номер земельного участка в документе указали

These versions are all understandable, but they can shift the emphasis slightly.

The original sentence sounds natural and somewhat formal. It puts the object first, then gives the location at the end.

Because Russian has no articles.

English must choose between a and the, but Russian does not mark that directly. So в документе could mean:

• in the document
• in a document

The exact meaning depends on context.

The same is true for кадастровый номер земельного участка:

• the cadastral number of the land plot
• a cadastral number of a land plot

In real use, context usually makes it clear which interpretation is intended.

It is often a formal legal/administrative term.

While it literally refers to a land plot or parcel, земельный участок is especially common in:

• property documents
• cadastral records
• land law
• official registration language

So in this sentence, the vocabulary sounds quite bureaucratic or official. A native speaker would recognize it as the kind of wording used in documents.

Кадастровый is an adjective meaning cadastral, that is, related to the official land/property registry.

It modifies номер:

• номер = number
• кадастровый номер = cadastral number

Then the phrase is expanded by земельного участка:

• кадастровый номер земельного участка = cadastral number of the land plot

So the structure is:

[adjective + noun] + [genitive phrase]

This kind of noun phrase is very common in formal Russian.

Yes, definitely.

Several things make it sound formal or administrative:

• кадастровый номер
• земельный участок
• the indefinite-personal указали
• the overall document-style wording

In everyday conversation, a speaker might use simpler wording if they were not talking in a legal or bureaucratic context. But for official language, this sentence sounds normal and natural.