Someone

using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication3
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("Add or Subtract? ");
            if (Console.ReadLine().Equals("Add"))
            {
                input(true);
            }
            else
            {
                input(false);
            }
        }
        public static void input(bool operation)
        {
            Console.Write("Enter Number A: ");
            string a = Console.ReadLine();
            Console.Write("Enter Number B: ");
            string b = Console.ReadLine();
            if (operation)
            {
                Console.WriteLine(a + " + " + b + " = " + add(Int32.Parse(a), Int32.Parse(b)).ToString());
            }
            else
            {
                Console.WriteLine(a + " - " + b + " = " + subtract(Int32.Parse(a), Int32.Parse(b)).ToString());
            }
            System.Threading.Thread.Sleep(System.Threading.Timeout.Infinite);
        }
        public static int add(int a, int b)
        {
            return a + b;
        }
        public static int subtract(int a, int b)
        {
            return a - b;
        }
    }
}