11 - 4 = (a)  

14 - 5 = (a)  

19 - 10 = (a)  

13 - 7 = (a)  

11 - 3 = (a)  

12 - 6 = (a)  

16 - 10 = (a)  

14 - 4 = (a)  

11 - 1 = (a)  

17 - 8 = (a)  

13 - 6 = (a)  

11 - 10 = (a)  

13 - 8 = (a)  

15 - 6 = (a)  

16 - 8 = (a)  

12 - 7 = (a)  

16 - 6 = (a)  

12 - 10 = (a)  

11 - 9 = (a)  

14 - 7 = (a)  

19 - 9 = (a)  

17 - 7 = (a)  

13 - 10 = (a)  

14 - 6 = (a)  

12 - 8 = (a)  

14 - 10 = (a)  

18 - 9 = (a)  

11 - 6 = (a)  

12 - 2 = (a)  

18 - 8 = (a)  

13 - 9 = (a)  

17 - 10 = (a)  

15 - 7 = (a)  

11 - 8 = (a)  

12 - 5 = (a)  

16 - 9 = (a)  

11 - 5 = (a)  

15 - 8 = (a)  

13 - 4 = (a)  

15 - 10 = (a)  

14 - 8 = (a)  

12 - 4 = (a)  

15 - 5 = (a)  

13 - 3 = (a)  

11 - 7 = (a)  

12 - 3 = (a)  

13 - 5 = (a)  

14 - 9 = (a)  

15 - 9 = (a)  

16 - 7 = (a)  

17 - 9 = (a)  

12 - 9 = (a)  

18 - 10 = (a)