     round
   end
 
+  % Returns the largest Integer less than or equal to self.
   def floor
     case self
     match x when x < 0 then (x - 1).truncate

module Numeric

  def abs
    Erlang.abs(self)
  end

  def abs2
    self * self
  end

    end
  end

  % Returns true if integer
  def integer?
    Erlang.is_integer self
  end

  % Returns true if zero
  def zero?
    self == 0
  end

  % Returns true if not zero
  def nonzero?
    !zero?
  end
