'需引用Microsoft Script Control
Dim sc As New ScriptControl
Dim s(2) As String
Dim i1, i2, i3, i4, i5, i6, i7, i8 As Integer
Dim sExpression As String
s(0) = "": s(1) = "+": s(2) = "-"
's(0)为前后二数合并,s(1),s(2)分别为+,-法
sc.Language = "vbscript"
For i1 = 0 To 2
For i2 = 0 To 2
For i3 = 0 To 2
For i4 = 0 To 2
For i5 = 0 To 2
For i6 = 0 To 2
For i7 = 0 To 2
For i8 = 0 To 2
sExpression = 1 & s(i1) & 2 & s(i2) & 3 & s(i3) & 4 & s(i4) & 5 & s(i5) & 6 & s(i6) & 7 & s(i7) & 8 & s(i8) & 9
If sc.Eval(sExpression) = 100 Then List1.AddItem sExpression
Next i8
Next i7
Next i6
Next i5
Next i4
Next i3
Next i2
Next i1
用的是穷举法,不知你感不感兴趣。