numbers in words -5

in_words_-5.rb

class Integer
  def in_words
    if self < 20
      {0 => "\b",
       1 => "one", 
       2 => "two",
       3 => "three",
       4 => "four",
       5 => "five",
       6 => "six",
       7 => "seven",
       8 => "eight",
       9 => "nine",
       10 => "ten",
       11 => "eleven",
       12 => "twelve",
       13 => "thirteen",
       14 => "fourteen",
       15 => "fifteen",
       16 => "sixteen",
       17 => "seventeen",
       18 => "eighteen",
       19 => "nineteen"}[self]
    elsif self < 100
      "#{{20 => "twenty",
          30 => "thirty",
          40 => "forty",
          50 => "fifty",
          60 => "sixty",
          70 => "seventy",
          80 => "eighty",
          90 => "ninety"}[self - (self % 10)]} #{(self % 10).in_words}"
    end
  end
end