6-4= 13-14= 6+18= 12-10=
3-7= 5+5= 6+16= 18+2=
3-8= 6+2= 0-1= 1+11=
16+13= 13+12= 11-6= 7+0=
9-0= 8+1= 2-17= 2+13=
18+6= 2-17= 6+19= 16+14=
4-16= 6-16= 14-17= 4-1=
14-17= 18+10= 4-8= 11+19=
0-11= 17+9= 3+1= 3-17=
1+9= 4-7= 5-11= 1-1=