using System;

public class Program

{

    public static void Main()

    {

        int sum = 0;

        bool addmore = true;

        bool submore = true;

        bool multimore = true;

        bool divmore = true;

        Console.WriteLine("Do you want to add (1), subtract (2), multiply (3), or divide (4).");

        int arithmetic = Convert.ToInt32(Console.ReadLine());

        Console.WriteLine("How many numbers do you want to compute?");

        int numberadding = Convert.ToInt32(Console.ReadLine());

        switch (arithmetic)

        {

            case 1:

                addmore = true;

                submore = false;

                multimore = false;

                divmore = false;

                break;

            case 2:

                addmore = false;

                submore = true;

                multimore = false;

                divmore = false;

                break;

            case 3:

                addmore = false;

                submore = false;

                multimore = true;

                divmore = false;

                break;

            case 4:

                addmore = false;

                submore = false;

                multimore = false;

                divmore = true;

                break;

        }

        while (addmore == true)

        {

            Console.WriteLine("Please input your number.");

            int number = Convert.ToInt32(Console.ReadLine());

            sum = sum + number;

        }

        while (submore == true)

        {

            Console.WriteLine("Please input your number.");

            int number = Convert.ToInt32(Console.ReadLine());

            sum = sum - number;

        }

        while (multimore == true)

        {

            Console.WriteLine("Please input your number.");

            int number = Convert.ToInt32(Console.ReadLine());

            sum = sum * number;

        }

        while (divmore == true)

        {

            Console.WriteLine("Please input your number.");

            int number = Convert.ToInt32(Console.ReadLine());

            sum = sum / number;

        }

        Console.WriteLine(sum); 

    }

}

​