13-12=

17-0=

19+0=

18-12=

12-11=

18-3=

13-7=

13-9=

14+4=

6+6=

6+13=

14-11=

14-14=

11-4=

9+9=

2+10=

3+12=

1+17=

15+4=

13-6=

20-1=

16+1=

4+16=

15-0=

16-8=

20-15=

11-4=

14+2=

15-4=

7+6=

18-8=

12+3=

5+12=

20-12=

12-12=

17-3=

14-11=

19-8=

7+7=

11-6=

18-15=

17-11=

18+1=

14-9=

12-2=

12-12=

15-8=

6+13=

15+5=

13+5=