XL 2016 SOMME CELLULE

Dim ok As Boolean
Private Sub Worksheet_Change(ByVal Target As Range)
Dim valeur
If ok = True Then Exit Sub
valeur = Target
If Not Intersect(Target, Range("A1")) Is Nothing Then
    ok = True
    Application.Undo
    Target = Target + valeur
End If
ok = False
End Sub

Private Sub Worksheet_Change(ByVal Target As Range)
    If Target <> "" Then
        Application.EnableEvents = False
        valsaisie = Target
        Application.Undo
        If Left(Target.Formula, 1) = "=" Then
            Target.Formula = Target.Formula & "+" & Trim$(Str$(valsaisie))
        Else
            Target.Formula = "=" & Trim$(Str$(valsaisie))
        End If
        Application.EnableEvents = True
    End If
End Sub

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    Static AncValeurC As String
    Static AncValeurD As String
    Static AncValeurE As String
    On Error GoTo Sortie
    Application.ScreenUpdating = False
    Application.EnableEvents = False
    If Not Intersect(Target, Columns("C")) Is Nothing Then
        AncValeurC = Target
    ElseIf Not Intersect(Target, Columns("D")) Is Nothing Then
        AncValeurD = Target
    ElseIf Not Intersect(Target, Columns("E")) Is Nothing Then
        AncValeurE = Target
    End If
Sortie:
    Application.EnableEvents = True
End Sub

Private Sub Worksheet_Change(ByVal Target As Range)
    Static AncValeurC As String
    Static AncValeurD As String
    Static AncValeurE As String
    On Error GoTo Sortie
    Application.ScreenUpdating = False
    Application.EnableEvents = False
    If Not Intersect(Target, Columns("C")) Is Nothing Then
        If Target.Count > 1 Then GoTo Sortie
            If Target = "" Then
                AncValeurC = ""
                GoTo Sortie
            End If
            If AncValeurC <> "" Then Target = Target + AncValeurC * 1
        AncValeurC = Target
    ElseIf Not Intersect(Target, Columns("D")) Is Nothing Then
        If Target.Count > 1 Then GoTo Sortie
            If Target = "" Then
                AncValeurD = ""
                GoTo Sortie
            End If
            If AncValeurD <> "" Then Target = Target + AncValeurD * 1
        AncValeurD = Target
    ElseIf Not Intersect(Target, Columns("E")) Is Nothing Then
        If Target.Count > 1 Then GoTo Sortie
            If Target = "" Then
                AncValeurE = ""
                GoTo Sortie
            End If
            If AncValeurE <> "" Then Target = Target + AncValeurE * 1
        AncValeurE = Target
    End If
Sortie:
    Application.EnableEvents = True
End Sub

Private Sub Worksheet_Change(ByVal Target As Range)
If Not Application.Intersect(Target, Range("C:E")) Is Nothing Then
    If Target <> "" Then
        Application.EnableEvents = False
        valsaisie = Target
        Application.Undo
        If Left(Target.Formula, 1) = "=" Then
            Target.Formula = Target.Formula & "+" & Trim$(Str$(valsaisie))
        Else
            Target.Formula = "=" & Trim$(Str$(valsaisie))
        End If
        Application.EnableEvents = True
    End If
End If
End Sub