prijateljima

In a sentence

• Idem s prijateljima na večeru.

  I am going to dinner with friends.

  In this sentence, 'prijateljima' is the instrumental case of 'prijatelji', meaning 'friends', and is used to denote accompaniment.

• Pričam s prijateljima o planovima za vikend.

  I am talking with friends about weekend plans.

  Here, 'prijateljima' is again in the instrumental case, which is used to indicate the entity with whom the action of the verb 'pričam' (am talking) is performed.

• Pomažem prijateljima s njihovim zadatkom.

  I am helping friends with their task.

  In this case, 'prijateljima' is in the dative case, used here to denote the indirect object receiving the action of the verb 'pomažem' (am helping).