Private Sub Worksheet_Change(ByVal Target As Range)
With [A1] 'cellule à adapter
Set Target = Intersect(Target, .Cells)
If Target Is Nothing Then Exit Sub
If Not IsNumeric([Memo]) Then ThisWorkbook.Names.Add "Memo", 0 'nom défini
Application.EnableEvents = False 'désactive les évènements
.Value = [Memo] + Val(Replace(.Text, ",", "."))
.Select
Application.EnableEvents = True 'réactive les évènements
ThisWorkbook.Names.Add "Memo", .Value 'nom défini
End With
End Sub