-3-[-5+(1-0.2*5分之3)/(-2)]
=-3-[-5+(1-1/5*3/5)/(-2)]
=-3-[-5+(1-3/25)/(-2)]
=-3-[-5+(22/25)/(-2)]
=-3-[-5+22/25*(-1/2)]
=-3-[-5-11/25]
=-3+5+11/25
=2+11/25
=2又11/25