中国小学5、6年级算术题：1 / (1/4 + 1/9) = 36/13 ≈ 2.77小时。

来源: 老马识途于 2017-02-01 01:01:50 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

WENXUECITY.COM does not represent or guarantee the truthfulness, accuracy, or reliability of any of communications posted by other users.