送交者: 吴礼 于 2006-3-04, 15:14:47:

回答: I'll never think of these kind of tricks. 由 mangolasi 于 2006-3-04, 15:03:11:

I did not invent this method. It was taught in my high school math class.

• No, I've never seen this before. - mangolasi (49 bytes) 2006-3-04, 15:24:13

加跟贴