Yadunno
Yadunno is a shorter version of saying "I don't know".
Dunno is a short version of saying "don't know" so yadunno would be "I don't know".
Dunno is a short version of saying "don't know" so yadunno would be "I don't know".
Person 1: Do you want the last half of my PB&J sandwich? I'm unusually full.
Person 2: Yadunno!
Person 2: Yadunno!