7+8= 12-7= 4+9= 8+3-7=
5+6= 7+5= 6+8= 17-9-1=
14-6= 13-5= 16-9= 6+7-5=
14-7+5= 12-6+8= 17-8-3=
11+4-8= 9+5+6= 11-6+7=