13-6= 8+7= 11-3= 14-5= 6+9=
15-7= 17-8= 14-7= 9+6= 11-6=
12-7= 3+8= 14-6= 13-5= 4+8=
12-9= 8+6= 16-7= 13-4= 11-9=
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