Translation:I practice the piano.
Just an observational comment. Actually I have put that and was accepted (7th Jan 19). However, although that's probably the most common way of saying this, the sentence refers to practising piano when it should say "I practice 'playing' the piano". (I teach piano should really be I teach piano playing). It's easily over-looked that we have many sentences shortened by ommision of important words and we know how frustrating that is sometimes, when faced with this in the languages we learn.