420+330=
578-200=
660+140=
818-178=
440-170=
562-142-110=
720+180-400=
305+195+162=
480+300=
520+80=
900-(500+150)=
240+120=
780-650=
750+250-600=
500+370=
980-180-200=
1000-300-450=