beginner: how can i convert int to a decimal with comma : 

            Console.Write("Hoeveel worpen wil je simuleren: ");
            int worpen = int.Parse(Console.ReadLine());
            
            

            Random r = new Random(worpen);
            int willekeur = r.Next(1, worpen);
            double willekeur1 = willekeur;
            Math.Round(willekeur1);


            for (int i = 1; i <= 12; i++)
            {
                Console.WriteLine("ik gooide "+willekeur+" ("+Math.Round(willekeur1,2,)+")"); 
                willekeur = r.Next(1, worpen);
                
            }
            Console.ReadLine();
   I want that ' willekeur1 ' a  number which contains a decimal comma is. so example: 12456--> 12,456 