void Main()
{
  var humanizer = new HumanizerService();
  Console.WriteLine(humanizer.ToWords(1m));
  Console.WriteLine(humanizer.ToWords(1.09m));
  Console.WriteLine(humanizer.ToWords(1.9m));
  Console.WriteLine(humanizer.ToWords(1.99m));
  Console.WriteLine(humanizer.ToWords(12.99m));
  Console.WriteLine(humanizer.ToWords(123.99m));
  Console.WriteLine(humanizer.ToWords(1234.99m));
  Console.WriteLine(humanizer.ToWords(12345.99m));
  Console.WriteLine(humanizer.ToWords(123456.99m));
  Console.WriteLine(humanizer.ToWords(1234567.99m));
  Console.WriteLine(humanizer.ToWords(12345678.99m));
  Console.WriteLine(humanizer.ToWords(123456789.99m));
  Console.WriteLine(humanizer.ToWords(1234567890.99m));
}

public class HumanizerService
{
  public string ToWords(decimal input)
  {
    var decimals = (int)((input - Math.Truncate(input)) * 100);
    var result = string.Format("{0}/{1}", ((int)input).ToWords(CultureInfo.GetCultureInfo("it-IT")), decimals);
    return result;
  }
}