Start training
CaseSingularPlural
Nominativeименительный · кто? что?тренер тренеры the subject: who or what acts
Accusativeвинительный · кого? что?тренера тренеров the direct object of the verb
Genitiveродительный · кого? чего?тренера тренеров possession, absence, "of"-phrases
Dativeдательный · кому? чему?тренеру тренерам the receiver: to or for someone
Instrumentalтворительный · кем? чем?тренером тренерами the tool or companion: with, by
Prepositionalпредложный · о ком? о чём?тренере тренерах location and topics: in, at, about

Тренер is animate, so its accusative copies the genitive: the form after "I see..." matches the form after "of".

Look up any other word in the Russian declension tool, see where тренер ranks in the most common Russian words, or start from Russian cases explained if the table above is new territory. More vocabulary lives in Russian words by topic and Russian phrases.

12 forms is a table. Using them is a skill.

Slova drills тренер and every word like it with typed case endings, checked letter by letter.

Train this in Slova