Factorial C# v2

using System;

namespace Factorial
{
    class Program
    {
        static void Main(string[] args)
        {
            int val;
            while (!int.TryParse(Console.ReadLine(), out val))
            {
                Console.WriteLine("Enter number: 2-9");
            }
            ShowFactoria(fromNum: val); // this will do what you asked @abdul :)

    /*
            int factorial;
            while (!int.TryParse(Console.ReadLine(), out factorial))
            {
                Console.WriteLine("Invalid number entered, make sure you entered a n: 0-10");
            }
            int result = 0;
            bool hit = true;
            for (int i = factorial - 1; i > 0; i--)
            {
                if (hit)
                {
                    result = factorial;
                    hit = false;
                }
                result *= i;
            }
            Console.WriteLine(result);
    */
            Console.ReadLine();
        }
        private static void ShowFactoria(int fromNum, int to = 0)
        {
            if (fromNum < to)
            {
                Console.WriteLine("from can't be less than to!!!");
                return;
            }
            if (to < -1)
            {
                Console.WriteLine("to can't be less than 0");
            }
            // You can do some other check here...

            long temp = 0;
            bool hit = true;
            long result = 0;
            // 10 * 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1
            for (int i = fromNum; i > to; i--)
            {
                if (hit)
                {
                    temp = i * (i - 1);
                    hit = !hit;
                }
                else
                {
                    temp *= (i - 1);
                }
                if (i - 1 > 1)
                {
                    Console.WriteLine(" + {0}", temp);
                    result += temp;
                }
                //Console.WriteLine(string.Format("{0} * "))
            }
            Console.WriteLine("The addition of the !{0} shriek is: {1}", fromNum, result);
            Console.ReadLine();
        }
    }
}
By: @ivandrofly