Private Sub Worksheet_Change(ByVal r As Range)
Set r = Intersect(r, [A:A], Me.UsedRange)
If r Is Nothing Then Exit Sub
Application.EnableEvents = False
For Each r In r 'si entrées multiples
If r.Value2 Like "######" Then
r = "=--(""1/" & Right(r.Value2, 2) & "/" & Left(r.Value2, 4) & """)"
If IsDate(r) Then r = r Else r = ""
End If
Next
Application.EnableEvents = True
End Sub