3 + (a)   = 4

(a)   + 6 = 7

(a)   + 3 = 9

4 + (a)   = 6

3 + (a)   = 5

5 + (a)   = 10

(a)   + 2 = 8

(a)   + 2 = 7

3 + (a)   = 6

4 + (a)   = 7

5 + (a)   = 6

(a)   + 4 = 6

(a)   + 4 = 7

2 + (a)   = 7

3 + (a)   = 8

5 + (a)   = 5

(a)   + 4 = 6

(a)   + 2 = 9

2 + (a)   = 8