8 - 4

(a)  

23 + 9

(a)  

8-3

(a)  

29 + 15

(a)  

16 - 6

(a)  

6 - 5

(a)  

70 + 89

(a)  

25 + 73

(a)  

-6 + 80

(a)  

3 x 15

(a)  

24 - 10 + 3

(a)  

16 + 8 + 3 + 4

(a)  

23 -5 + 10 +2 +50

(a)  

700 + 250 + 250 200

(a)  

375 - 198

(a)  

856 - 595

(a)  

6 098 093 + 498 200

(a)  

7 693 403 - 3 043 967

(a)