public decimal Calculate(string calculate, decimal num1, decimal num2) { //int first = Convert.ToInt32(num1); //int second = Convert.ToInt32(num2); switch (calculate) { case "1": Addition addition = new Addition(); answer = addition.AddThese(num1, num2); Console.WriteLine("Your answer is: " + answer); break; case "2": Subtraction subtraction = new Subtraction(); answer = subtraction.SubtractThese(num1, num2); Console.WriteLine("Your answer is: " + answer); break; case "3": Multiply multiply = new Multiply(); answer = multiply.MultiplyThese(num1, num2); Console.WriteLine("Your answer is: " + answer); break; case "4": Divide divide = new Divide(); answer = divide.DivideThese(num1, num2); Console.WriteLine("Your answer is: " + answer); break; case "5": Exponential exponential = new Exponential(); exponential.ExponentThese(num1, num2); break; default: Console.WriteLine("Not a valid choice!"); break; } return answer; }