'Benötigt werden: 2 Textboxen, 2 Labels, 1 Timer, 1 Commandbutton
Option Explicit
Private Wert&
Private Summe#
 
Private Sub Command1_Click()
 
Wert = Val(Text1.Text)
If Wert < 1 Then Exit Sub
Text2.Text = ""
Summe = 0
Timer1.Enabled = True
 
End Sub
 
Private Sub Form_Load()
 
Timer1.Enabled = False
Timer1.Interval = 100
Command1.Caption = "Start"
Label1.Caption = ""
Label2.Caption = ""
Text1.Text = 100
Text2.Text = ""
Text2.Enabled = False
 
End Sub
 
Private Sub Timer1_Timer()
 
Summe = Summe + 1 / (Wert * Wert * Wert * Wert)
Label1.Caption = Wert
Label2.Caption = Summe
Wert = Wert - 1
If Wert = 0 Then
  Timer1.Enabled = False
  Text2.Text = "Pi ~ " & (90 * Summe) ^ (1 / 4)
  Text2.Enabled = True
End If
 
End Sub

Gruss,

Zardoz