9+1= 10-7= 8-8= 13-2=
9-4= 8+4= 12+3= 9+8=
4+6= 11+7= 16-3= 7+6=
10+6= 9+9= 17-5= 8+8=
8+2-5= 7+7-4= 9+1+5= 15-5-6=