40-7= 20+80= 23-8= 52-(20+20)=
7+23= 90-20= 3+29= 8+(26+4)=
42+6= 41+9= 80-40= 36+(5-3)=
92-3= 92-70= 51-4= 30+8-5=
9+27= 17-9= 79-40= 17-8+63=