vb.net

Public Class Form1
    Dim aNum As Integer = 0
    Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
        'Me.Hide()
        setTimer(10)

    End Sub

    Private Sub tmath()
        Dim a, r As Integer
        a = 5
        r = a + 5
        MsgBox("R: " & r)
    End Sub

    Private Sub tmath1()
        Dim a, r As Integer
        a = 10
        r = a + 5
        MsgBox("R1: " & r)
    End Sub

    Private Sub setTimer(ByVal intNum As Integer)
        aNum = aNum + 1

        If aNum > intNum Then
            Timer1.Stop()
            tmath()
            Timer1.Start()
            If aNum > 15 Then
                aNum = Nothing
                Timer1.Stop()
                tmath1()
                Timer1.Start()
            End If
        End If
    End Sub

End Class