20 + 5 =

(a)  

15 - 7 =

(a)  

9 - 2 =

(a)  

4 + 17 =

(a)  

6 +3 =

(a)  

8 + 8 =

(a)  

6 + 8 =

(a)  

18 - 11 =

(a)  

14 - 4 =

(a)