Public Class Form1
    Function check(ByVal num)
        Label2.Text = Label2.Text + ToString(num)
    End Function

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        check(0)
        check(1)
        check(2)
        check(3)
        check(4)
        check(5)
        check(6)
        check(7)
        check(8)
        check(9)
        check(10)
        check(11)
        check(12)
        check(13)
        check(14)
        check(15)
        check(16)
        check(17)
        check(18)
        check(19)
        check(20)
    End Sub
End Class