# File lib/Fraccion.rb, line 65
   def abs
        if (@n < 0) ^ (@d < 0)
           if @n < 0
                Fraccion.new(@n*-1, @d)
           else
                Fraccion.new(@n, @d*-1)
           end

                elsif (@n < 0) && (@d < 0)
                        Fraccion.new(@n*-1, @d*-1)

                      else
                         Fraccion.new(@n, @d)
                end
     end