6+9= 15-7= 3+9= 9+9=
7+8= 16-8= 8+8= 20-13=
8+6= 9+2= 6+7= 9+2=
8+3= 2+9= 9+7= 5+7=
13-8= 5+7= 5+7= 5+9=
7+5= 20-1= 8+5= 10-8=
9+4= 15-7= 5+7= 6+9=
10-2= 7+8= 12-5= 13-8=
20-2= 10-3= 12-5= 6+6=
10-8= 3+8= 8+4= 17-8=