static void Main(string[] args)
{
var gradebook = new Book("The great book");
gradebook.AddGrade(95.2);
gradebook.AddGrade(91.2);
gradebook.AddGrade(77.2);
gradebook.ShowStatictics();
var stats = gradebook.GetStatistics();
Console.WriteLine($"The lowest grade is {stats.LowGrade}");
Console.WriteLine($"The highest grade is {stats.HighGrade}");
Console.WriteLine($"The average grade is {stats.Average:N1}");
}
