15-8= 86-32= 12+18= 20+15-6=
6+35= 45-40= 27+30= 82-50-30=
29+11= 16+7= 90-60= 15+9+7=
50+50= 40-8= 41+9= 35-30+10=
20-13= 9+6= 24-6= 70+15-35=