c#练习题求平均分和排序

困扰我几天了新手还不是很懂求解

            List<int> list1 = new List<int>() { 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 };
            var avgResutl = list1.Average();
            Console.Write("平均值:{0}", avgResutl);

            list1 = list1.OrderBy(s => s).ToList();
            Console.WriteLine("从小到大排列");
            foreach (var l in list1)
            {
                Console.WriteLine(l);
            }

            Console.ReadKey();