private string CalcOtherNumbers(int number)
 {
     romanNumbers.Reset();
     while (romanNumbers.MoveNext())
     {
         if (number < romanNumbers.Current.Number)
         {
             return(CreateExtraNumbers(number));
         }
     }
     // for now not bigger than 3000
     if (number > 1000)
     {
         return(CreateExtraNumbers(number));
     }
     return(string.Empty);
 }