YOU SAID:

you cannot even play the piano and sing at the same time

INTO JAPANESE

ピアノを弾いて歌うこともできません

BACK INTO ENGLISH

I can't play the piano and sing

INTO JAPANESE

ピアノを弾いて歌えない

BACK INTO ENGLISH

I can't sing by playing the piano

INTO JAPANESE

ピアノを弾いて歌えない

BACK INTO ENGLISH

I can't sing by playing the piano