public void Begin()
{
UserInput userInput = new UserInput();
AbsProblem problem = null;
Console.WriteLine("Which Lesson?: ");
DisplayLessons();
int choice = userInput.intUserInput();
problem = GetLesson(choice);
if (problem != null)
{
problem.Begin();
}
}
protected void AddLessons(int key, AbsProblem value)
{
_lessons.Add(key, value);
}