static void Main(string[] args) { ICalculadora iCalculadora = new Calculadora(); int operation; int result = 0; Console.WriteLine("Type you first number :"); string stringnum1 = Console.ReadLine(); int num1 = Convert.ToInt32(stringnum1); Console.WriteLine("Type you second number :"); string stringnum2 = Console.ReadLine(); int num2 = Convert.ToInt32(stringnum2); Console.WriteLine("Enter the operation 1) + 2) - 3) * 4) / "); operation = int.Parse(Console.ReadLine()); switch (operation) { case 1: result = iCalculadora.Suma(num1, num2); break; case 2: result = iCalculadora.Resta(num1, num2); break; case 3: result = iCalculadora.Multiplication(num1, num2); break; case 4: result = iCalculadora.Division(num1, num2); break; } Console.WriteLine("\nResult " + result); Console.ReadKey(); }