8+9= 8+4= 6+7= 9+9=
11-8= 13-6= 16-9= 13-9=
16-9+8= 14-8+4= 12-9+7= 16-8+4=
17-8-3= 10+3-8= 17-8+7= 3+8-2=
15-810 11-311-4 18-912-2
13-95 15-1014-9 13-713-6