# Quod Erat Demonstrandum

## 2008/09/26

### 中二數學問題之有效數字

Filed under: Junior Form Mathematics — johnmayhk @ 9:37 上午

## 3 則迴響 »

1. interesting question, and it is time to show whether one can teach students well or not…

I think I will try to ask the student what happens if we correct 0.2541 to 2 sig. fig.
then he should realize his answer, 0.254, is not the maximum value
then carry on with 0.2542, 0.2543, …, 0.2549, 0.25499, 0.254999,…
hopefully he can get a sense that x can be any value below 0.255

迴響 由 Daniel — 2008/09/26 @ 10:13 上午 | 回應

2. 我想我們很難向現代的中二學生
去解釋0.2549, 0.25499等概念
因為他們所接觸的數學題
為了方便
其數值每每是整數
更遑論向中二學生解釋
為何x沒有maximum value吧
哈哈

迴響 由 皮旦 — 2008/09/26 @ 11:36 上午 | 回應

3. @Daniel

That’s exactly the way I told the student 0.254 is not the max.

@皮旦

Perhaps the question is a question itself, it means the ‘least upper bound’, not ‘maximum’.

迴響 由 johnmayhk — 2008/09/27 @ 10:46 上午 | 回應