Private Sub cmdQuersumme_Click()
    Dim Zahl As Long
    Dim Quersumme As Long
    Dim x As Long
 
    Zahl = "123"
 
    If IsNumeric(Zahl) Then
        For x = 1 To Len(Zahl)
            Quersumme = Quersumme + Mid(Zahl, x, 1)
        Next x
    End If
 
    MsgBox Quersumme
End Sub