11-2= 13+10= 50-40= 20+5= 15-9-1=
15-5= 18-9= 80-70= 77-7= 14-5+20=
50+4= 65-60= 13-5= 16-8= 13-6+7=
40-30= 12+20= 14-5= 82-2= 50-30+8=
16-7= 42+8= 27+30= 30+60= 12-（ ）=7
6+27= 50-5= 8+18= 31+9= （ ）-6=9
35-5= 64-40= 28-3= 34-6= 18-9+8=
25+4= 47+7= 23-9= 8+45= 24-20+73=
11-5= 27-3= 30+50= 14-9= 50+16 =
16-8= 45-7= 43-20= 12-4= 14-6 =
46+20= 79-40= 55+30= 68-40=
46+2= 79-4= 85-3= 68-4=
46+9= 79+5= 85+7= 68+6=
