There are four cases (= Kasus) in German: Nominativ (= nominative; that’s the case of the subject of the sentence), Akkusativ (= accusative), Dativ (= dative) and Genitiv (= genitive).
Depending on the case, German nouns, adjectives, articles and numerals are declined: they change their forms. The case of a word or a part of the sentence is mostly determined by a verb or a preposition.
A table containing the German nouns, articles and adjectives in all their forms you can find HERE.
In the following exercises there is always one part of the sentence highlighted. Click on the case which belongs to the marked noun.
Have fun!