請指教小學數學題

ChiChiPaPa

wunma說的就是現在數學課程的要求。

不過，我小時候，的確是學 7個x9。

我始終覺得這些數式要求是無謂的執著。

wunma 寫道:
ChiChiPaPa 的乘數觀念非常對, 但數式觀念不容忽視.

舉另一例:
有糖28粒, 分別放入盒子, 每盒可放4粒, 問共有糖多少盒?
做法:

共有糖:
28 ÷ 4
=7 (盒)
即: 共有糖7盒, 所以不能寫成:
28粒÷4粒=7 (盒) 因為"粒"÷"粒"不可能="盒", 所以一定不能在數式上亂加名數.

版主所舉的例子:
聖誕樹上有9種不同顏色的小球,每種顏色有7個,共有小球多少個?

做法－
共有小球：
７ｘ９
＝６３（個）
註：留意以上的應用題, 一定要有"點題", 所以答案是: 共有小球63個.

所以不能寫成:
7x9 個, 7個x9,7個x9個

塞曼莎

wunma,

"點題"唔係應該,

聖誕樹上共有小球63個

或

聖誕樹上共有顏色小球63個

  

15分

Y2KChild,

The Balance of Unit.

It may be too hard to understand for few BK parents if they are not study Science subject in the past.  I don't think this concept will be covered in Primary School or even Secondary School.

too bad.   

15分

wunma,

His equation is absolutely correct.
Forget about the number first, you calculated the result of the "Unit"

粒 ÷ 粒/盒 = 粒 x 盒/粒=盒

Number side:

28÷ 4= 7

Therefore,

The answer is 7盒.

It is because your "unit" is not balance in your equation; therefore, you only can show 7(盒), not 7盒.

wunma 寫道:
Y2KChild

請問你是老師嗎? 唔係你話對就對, 錯就錯, 要有根據的. 你話我"absolutely wrong", 憑什麼呢? 你有否小朋友正就讀小學, 或近年曾讀小學?

相反, 你那條"28粒 ÷ 4粒/盒 = 7盒", 真是見所未見, 請引述從何而來?


[quote]
Y2KChild 寫道:
wunma

Please don't give wrong answers to other BK parents. Mathematically, the balance of unit is the most importance otherwise it is absolutely wrong!

For your example: the correct way of writing the mathematical equation is:

28粒 ÷ 4粒/盒 = 7盒

[/quote]

cow

7個x9 =63個  √
(7x9)個 = 63個  √
7x9 = 63個  √ (可以最後才加單位)
9x7 = 63個  (好似唔係咁好)
9x7個 = 63個 (好似唔係咁好)
28粒 ÷ 4(粒/盒) = 7盒 (有啲深但是正確的)

15分

"可以最後才加單位"-->absoultely wrong.

cow 寫道:
7個x9 =63個  √
(7x9)個 = 63個  √
7x9 = 63個  √ (可以最後才加單位)
9x7個 = 63個 (好似唔係咁好)

15分

"我相信單位不能這樣當數字計"

This is what Y2KChild said, Balance of Unit.  It is an introductory section in University course, such as Chemistry, and Engineering, etc.

15分

書是死的,學校的老師是幚助小朋友學習,小朋友要有求正的思維.

如你所說就是死讀書.

ChiChiPaPa

15分,Y2kChild,

WunMa只是說出新的小學課程要求，請問兩位有沒有小朋友讀緊初小？

WunMa,

我小時候學的除數是有學同名數相除，有說及Y2kChild所說的公式。

相信台灣還是用這方法教，妳可以參考以下的台灣網頁。(相信妳已明白我所說的執著。)

http://www.kcta.org.tw/forum/wage.asp?TopicId=403

例二：秀文做了67個布丁，每8個裝一盤，一共要幾個盤子，才能把布丁全部裝完？
一般的寫法是67個÷8個＝8 （盤）…..3個，理由是同名數相除得異名數，但異名數之名為何，只能各憑理解各顯神通。其實是「個÷個/盤＝盤…..個」，這個「盤」不是憑空躍出來的，它是有跡可尋，有道理的。完整寫法是67個÷8個/盤＝8盤…..3個，配合直式書寫更清楚單位運算。

cow

Y2KChild wrote,
"7x9 = 63個 √ (可以最後才加單位)" - Mathematically it is not correct because of the unit in the equation is not balanced.

聖誕樹上共有小球:7x9 = 63個
This is a kind of omission, just as Mrs M vs Mrs. M. (7x9) is a simple equation. Sometimes, we need to calculate several times and several lines of equations appear. We don't want to repeat so many units, therefore we just put the unit at the end of the answer. This is acceptable. Don't be too stright even in doing Mathematics.

15分

why don't we give them a correct concept at the beginning.