internal static void Run()
{
var menu = new Menu("Enter command: ");
menu.Add("a", "Add ten", AddTen);
menu.Add("b", "Multiply by four", MultiplyByFour);
menu.Add("c", "Subtract by five", SubtractByFive);
cc.DisplayMenu(menu);
DisplayNumber();
cc.DisplayMenu(menu);
DisplayNumber();
cc.DisplayMenu(menu);
DisplayNumber();
}