If we want to master Serbian, we have to deal with seven (that's right ... seven ...) cases.
Below we will give you an overview over those seven cases and their functions within a Serbian sentence.

1^rst case: Nominative

The subject of every Serbian sentence is in the nominative case.
If you are asking for the subject in a Serbian sentence, you use the interrogative pronouns Тко/ Tko? (who?-m/f) / Шта/ Što? (what?-n).

2^nd case: Genitive

The genitive in Serbian describes relations – like ownership, temporal relations or spatial distances.
We also use the genitive in Serbian when we talk about quantity and numbers of persons or things.
The genitive is used to describe the origin of persons or things.
Some Serbian prepositions demand to be combined together with a genitive form.

Also certain expressions of time only want to be seen and heard together with the genitive.
If you are asking for a genitive form in a Serbian sentence, you use the interrogative pronouns Кога?/ Koga? (whose?-m/f) or Чега/ Čega? (whose?-n).

3^rd case: Dative

The function of the dative in a Serbian sentence is to mark the indirect object.
If you analyse a Serbian sentence and you want find out where the dative form is located, you ask:
Кoму?/ Komu? (whom?, when the noun in the dative is animated)
Чемy?/ Čemu? (whom?, when the noun in the dative form is inanimated)

Some Serbian verbs are always followed by the noun in the dative, e.g.:

Also you need to get acquainted with Serbian prepositions that ask for the usage of the dative:
к/k, ка/ka, надомак/nadomak, насупрот/nasuprot, према/prema, против/protiv, упркос/uprkos, надохват/nadohvat

4^th case: Accusative

The function of the accusative in a Serbian sentence is to mark the direct object.
If you a searching for the accusative in a Serbian sentence, you ask:
Кога?/ Koga? (Who?)
Чега/ Čega? (What?)

The accusative is often used together with verbs that signalize a movement.

Some Serbian prepositions call for the use of the accusative, e.g.:

5^th case: Locative

A Serbian noun with a locative ending describes the whereabouts / the location of a person or an object.
If you try to track down a noun in the locative in a Serbian sentence, you ask:
Где / Gdje? (where?)
О чему/O čemu (where of?)

And please remember: the locative in Serbian always comes with a preposition!
It can come with the following:

6^th case: Instrumental

With the instrumental case Serbian describes the means / the device with what an action is executed.
With the help of these question words, you can identify Serbian nouns with instrumental endings:
Са ким/S kim? (with whom?)
Чиме/Čime? (with what?)

Please, try to get acquainted with this new case ending.
The English language doesn't know a case like this.

These prepositions stand together with instrumental case endings:

7^th case: Vocative

We find vocative case endings in Serbian whenever we want to address another person.