2

(a)  

3

(a)  

4

(a)  

10

(a)  

5

(a)  

6

(a)  

7

(a)  

8

(a)  

9

(a)  

20

(a)  

30

(a)  

40

(a)  

50

(a)  

60

(a)  

70

(a)  

80

(a)  

90

(a)  

0

(a)