Mine

class Array  def inject(n)     each { |value| n = yield(n, value) }     n  end  def sum    inject(0) { |n, value| n + value }  end  def product    inject(1) { |n, value| n * value }  endend[ 1, 2, 3, 4, 5 ].sum 	» 	15[ 1, 2, 3, 4, 5 ].product 	» 	120