static void Main(string[] args) { Calculator calc = new Calculator(); double a = 4.5, b = 2.5; double result = calc.Add(a, b); Console.WriteLine($"result = {result}"); double result2 = calc.Subtract(a, b); Console.WriteLine($"result2 = {result2}"); double result3 = calc.Mult(a, b); Console.WriteLine($"result3 = {result3}"); double result4 = calc.Div(a, b); Console.WriteLine($"result4 = {result4}"); }