回复：印度同事出的题，瓦爷用了5妙钟，都来试试。

来源: 于 2010-04-21 12:33:04 [旧帖] [给我悄悄话] 本文已被阅读：次

This should not be a tricky question. "+" should be replaced with an unknown operation (?) to make it a valid math exercise.