2+1= 5-3= 4+4= 9-2= 13-8=
5-0= 5+5= 10-3= 3+7= 16-9=
12+3= 10+7= 18-7= 16-10= 11-6=
9+4= 8+8= 7+7= 6+5= 20-10=