As you already know, adjectives take an ending when they come directly before the noun they describe. The adjective endings vary depending on the gender, number, and case of the noun which they describe.

Adjective endings in the dative case are a bit simpler than the ones you learned before 🙂 In the dative case, if the adjective is preceded by a der-word (e.g., definite article), all adjectives (regardless of the gender of the noun) add -en. As you learned in Einheit 5.8, the masculine form of the definite article changes from der to dem, the feminine definite article changes to der, the neuter article changes to dem, and the plural article changes to den.

In the dative case, if the adjective is preceded by an ein-word (e.g., indefinite article, “kein”, or any possessive adjective mein, dein, sein/ihr/sein, unser, euer, ihr/Ihr), the same rules as with der-words apply: the adjective ending is -en.

*Achtung* All nouns (except for some proper names) add -n in the dative plural, unless their plural ends in -s, for example:

die Freunde (Nom. pl.) → den Freunden (Dat. pl.)

die Bücher (Nom. pl.) → den Büchern (Dat. pl.)

die Hobbys (Nom. pl.) → den Hobbys (Dat. pl.)