Mirate este ejemplo d eloq ue digo, es complicado hacer una resta como la quieres hacer...
Código (Vb) [Seleccionar]
Option Explicit
Private Type udtDouble
value As Double
End Type
Private Type udtStr
value As String * 8
End Type
Private Sub Form_Load()
Dim One As udtDouble, _
Two As udtDouble, _
Res As udtDouble
Dim tStr As udtStr
tStr.value = "8" '1000 0000
LSet One = tStr
tStr.value = "2" '0010 0000
LSet Two = tStr
Res.value = (One.value - Two.value) ' 1000 0000 - 0010 0000 = 11000000 = (192 >> 4) = 12
LSet tStr = Res
Debug.Print tStr.value '= 192
Debug.Print Asc(tStr.value) '= 12
End Sub
Dulces Lunas!¡.