I learnt the above method in E-school

來源: 於 2009-07-22 23:36:15 [博客] [舊帖] [給我悄悄話] 本文已被閱讀：次

so the answer is yes, depending on who the student is.

you have already seen a yahoo software engineer does not know how to calculate 1+2+...+n. do you think you have any method work for all E-school student?