internal void RunCalculator()
 {
     UserInput = myInteractor.GetUserInput();
     if (myInputChecker.ValidInput(UserInput))
     {
         string answer = myCalculator.DoOperation(UserInput);
         myInteractor.GiveAnswer(answer);
     }
     else
     {
         myInteractor.TellUserWhatWrong(myInputChecker.ErrorMessage);
     }
 }