static void Main(string[] args) { //Console.WriteLine("Hello World!"); Arithmetic a1 = new Arithmetic(); a1.GetNumber(); Console.WriteLine("Choose\n1: Addition\n2: Subtraction\n3: Multiplication\n4: Division"); int caseSwitch = Convert.ToInt32(Console.ReadLine()); switch (caseSwitch) { case 1: Console.WriteLine(a1.Addition()); break; case 2: Console.WriteLine(a1.Subtraction()); break; case 3: Console.WriteLine(a1.Multiplication()); break; case 4: Console.WriteLine(a1.Division()); break; default: break; } }