Private Sub CommandButton1_Click()
 
Dim x As Double
Dim y As Double
Dim A As Double
Dim Summe As Double
Dim reihe_count As Double
Dim auswahl_x As Range
Dim auswahl_y As Range
Dim istart As Integer
Dim iend As Integer
Dim zaehler As Integer
 
Set auswahl_x = Range(RefEdit1.Value)
Set auswahl_y = Range(RefEdit2.Value)
 
reihe_count = auswahl_x.Rows.Count
 
istart = 1
iend = reihe_count
zaehler = istart
 
For zaehler = istart To iend
    Summe = (auswahl_y(zaehler + 0) + auswahl_y(zaehler + 1)) * (auswahl_x( _
      zaehler + 0) - auswahl_x(zaehler + 1))
Next zaehler
 
A = (Abs(Summe)) / 2
 
Label5.Caption = A
 
End Sub