Sub Calcul(ByVal TBx1 As MSForms.TextBox, ByVal TBx2 As MSForms.TextBox, ByVal TBx3 As MSForms.TextBox)
Dim N1 As Double, N2 As Double, Result As Double
If TBx1.Text = "" Or TBx2.Text = "" Then
MsgBox "Manque donnée !"
Exit Sub: End If
N1 = CDbl(TBx1.Text)
N2 = CDbl(TBx2.Text)
Result = N1 * N2
TBx3.Text = Result
End Sub