
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click, Button2.Click, Button3.Click, Button4.Click
        Dim Sum As Long
        Call Fact(sender.TAG, Sum)    'ʵSumͱβTotalһ£Long
        If sender. Tag = 7 Then Sum = Sum / 42 + Sum / 7 + Sum * 8     5!+6!+8!˴Sum=7!
        Label1.Text = sender. Text & " = " & Sum
    End Sub

Private Sub Fact(ByVal n As Integer, ByRef Total As Long)
        Dim i As Integer
        Total = 1
        For i = 1 To n
            Total = Total * i
        Next
End Sub
