def normalize_numbers(_numbers)
      numbers = _numbers.map(&:to_i)
      min = numbers.min
      numbers.map do |n|
        n - min
      end
    end
def normalize_numbers(_numbers)
      numbers = _numbers.map(&:to_i)
      min = numbers.min
      numbers.map do |n|
        n - min
      end
    end
Returns the normalized equivalent of a given list

   normalize_numbers([3, 4, 7])
   # => [0, 1, 4]

 @return [Fixnum] the normalized equivalent of the given +_numbers+