79-20= 64-7= 71-9= 26+4=
92-7= 60+30= 33-8= 53+30=
58+6= 75+10= 30+27= 42+9=
84-40= 90+9= 8+65= 69-55=
34+29= 73-27= 28+26= 85-27=
13+47= 68-18= 90-44= 46+42=