B=9, W=A+1, X=0 だな。

A=1, W=2
 56 + 87 = 57 + 86 = 143,
 65 + 78 = 75 + 68 = 143,
 56 + 78 = 58 + 76 = 134,

A=2, W=3
 64 + 87 = 67 + 84 = 151,
 47 + 68 = 48 + 67 = 115,

A=4, W=5
 26 + 87 = 27 + 86 = 113,
 
A=5, W=6
 34 + 78 = 38 + 74 = 112,
 34 + 87 = 37 + 84 = 121,
 43 + 78 = 48 + 73 = 121,

の9通り。