18 – 9 = 17 – 9 = 16 – 9 = 15 – 9 =

  
14 – 9 = 13 – 9 = 12 – 9 = 11 – 9 =

  
17 – 8 = 16 – 8 = 15 – 8 = 14 – 8 =

  
13 – 8 = 12 – 8 = 11 – 8 = 16 – 7 =

  
15 – 7 = 14 – 7 = 13 – 7 = 12 – 7 =

  
11 – 7 = 15 – 6 = 14 – 6 = 13 – 6 =

  
12– 6 = 11 – 6 = 14 – 5 = 13 – 5 =

  
12 – 5 = 11 – 5 = 13 – 4= 12 – 4=

  
11 – 4= 12 – 3 = 11 – 3 = 11 – 2 =
