並前往https://zh-cn.facebook.com/wonderfulmaths/posts/summation-notation-%E7%AC%AC%E4%B8%80%E5%9B%9Esummation-notation-%E7%9A%84%E4%B8%AD%E6%96%87%E6%98%AF%E9%80%A3%E5%8A%A0%E8%A8%98%E8%99%9F%E7%95%B6%E8%A6%81%E9%80%A3%E7%BA%8C%E6%8A%8A%E4%B8%80%E5%80%8B%E6%9C%89%E8%A6%8F%E5%BE%8B%E7%9A%84%E6%95%B8%E5%88%97%E7%9A%84%E6%89%80%E6%9C%89%E9%A0%85%E5%8A%A0%E8%B5%B7%E4%BE%86%E6%99%82%E6%88%91%E5%80%91%E4%BE%BF%E7%94%A8%E5%BE%97%E8%91%97%E9%80%99%E7%A8%AE%E8%A8%98%E8%99%9F/957075457676618/