Switch Aprende programación con ejercicios C# Sharp

using System;
public class Exercise44
{
    public static void Main()
    {
        int number;

        Console.Write("Number? ");
        number = Convert.ToInt32(Console.ReadLine());

        if ((number == 9) || (number == 10))
            Console.WriteLine("Sobresaliente");
        else if ((number == 7) || (number == 8))
            Console.WriteLine("Notable");
        else if (number == 6)
            Console.WriteLine("Bien");
        else if (number == 5)
            Console.WriteLine("Aprobado");
        else if ((number >= 0) && (number <= 4))
            Console.WriteLine("Suspenso");
        else
            Console.WriteLine("No válido");

        switch (number)
        {
            case 0:
            case 1:
            case 2:
            case 3:
            case 4:
                Console.WriteLine("Suspenso");
                break;
            case 5:
                Console.WriteLine("Aprobado");
                break;
            case 6:
                Console.WriteLine("Bien");
                break;
            case 7: goto case 8;
            case 8:
                Console.WriteLine("Notable");
                break;
            case 9:
                Console.WriteLine("Bajo, pero... ");
                goto case 10;
            case 10:
                Console.WriteLine("Sobresaliente");
                break;
            default:
                Console.WriteLine("Nota no válida");
                break;
        }
    }
}