5+7= 2+9= 13-3= 11-10=
1+9+7= 8-4= 8+8= 17-4=
9+1-6= 10-6+8= 7+6= 9+3=
10-7= 8+3+2= 18-3-5=
6+815 9+716
10-18+2 19-38+9