static void Main(string[] args)
        {
            Console.WriteLine("Please enter a string command either add, subtract, multiply or divide. Then enter two integer numbers.");
            string command = Console.ReadLine();
            int entered1 = int.Parse(Console.ReadLine());
            int entered2 = int.Parse(Console.ReadLine());

            if (command == "add")
            {
                int result = Add(entered1, entered2);
                Console.WriteLine(result);
            }

            if (command == "substract")
            {
                int result = Subtract(entered1, entered2);
                Console.WriteLine(result);
            }

            if (command == "multiply")
            {
                int result = Multiply(entered1, entered2);
                Console.WriteLine(result);
            }

            if (command == "divide")
            {
                int result = Divide(entered1, entered2);
                Console.WriteLine(result);
            }

        }

        static int Add(int number1, int number2)
        {
            return number1 + number2;
        }

        static int Subtract(int number1, int number2)
        {
            return number1 - number2;

        }

        static int Multiply(int number1, int number2)
        {
            return number1 * number2;

        }

        static int Divide(int number1, int number2)
        {
           return number1 / number2;

        }