17-6= 18-8= 19-10= 4+3= 2+7=
4+7= 18-11= 13-1= 5+12= 15-8= 16-3= 17+1= 17-5= 15-3= 5+14=
4+9= 4+5= 5+7= 16-1= 20-13=
9+6= 14-1= 9+1= 6+14= 14-1=
11+8= 10+4= 8+4= 20-10= 14-3=
7+12= 9+3= 9+4= 12+1= 2+9=
11+3= 13-3= 17-3= 14-5= 14+6= 11+2= 8+12= 20-12= 3+8= 5+10=
5+9= 9+2= 6+10= 12+4= 8+1=
2+7= 11+6= 17+3= 5+13= 11+1= 12+3= 2+5= 3+12= 19-7= 19-10= 20-8= 14+4= 11-1= 1+18= 18-11= 15-8= 10+6= 11+4= 17-10= 12+6= 11-3+2= 3+12-10= 15+3-17= 4+3-1= 19-18+3= 3+8+7= 14-4+1= 9-2+10= 9+1-3= 12-4+5= 12-10+7= 1+2-2=
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