Function Operation(Otype$, Plage)
Dim aux$, i As Byte, operateur$
Plage = Plage
If UBound(Plage) > 1 Then Plage = Application.Transpose(Plage)
aux = "A+S-M*D/"
i = InStr(aux, UCase(Left(Otype, 1)))
operateur = Mid(aux, i + 1, 1)
Operation = Evaluate(Join(Plage, operateur))
If IsError(Operation) Then Operation = "" 'facultatif
End Function