Ex3 would be my preferred method.

Sub ex1()
    For counter = 1 To 25
        If counter = 11 Then counter = 20
        Debug.Print counter
    Next
End Sub


Sub ex2()
    For counter = 1 To 25
        Select Case counter
            Case 1 To 10, 20 To 25
                Debug.Print counter
        End Select
    Next
End Sub


Sub ex3()
    main 1, 10
    main 20, 25
End Sub

Sub main(startat, endat)
    For counter = startat To endat
        Debug.Print counter
    Next
End Sub