p**j
发帖数: 7063 | 1 【 以下文字转载自 Joke 讨论区 】
发信人: DDavidd (bbdd), 信区: Joke
标 题: Re: 现在知道为什么美国人算术差了 (转载)
发信站: BBS 未名空间站 (Mon Dec 2 18:14:53 2013, 美东)
发信人: Coralreef (扇呼扇呼), 信区: Military
标 题: Re: 现在知道为什么美国人算术差了
发信站: BBS 未名空间站 (Sat Nov 30 14:51:00 2013, 美东)
ＬＤ华人上看到的贴，美国人算是没招了，小学数学老师。。。
我们四年级娃老师的数学水平 发贴心情 Post By：10/10/2013 5:52:00 PM
See the following emails:
Teacher's email:
As far as problem number 5, the expectation was for 1 to be subtracted from
623 to show that since we added 1 to 29 to make a ten, we had to subtract 1
from 653. So, the problem should have looked like:
653-29 = ?
Make a ten 29+1= 30
653-30=623
623-1=622
653-29=622
My original email (1st email):
I did notice that there is a grading mistake. I had attached that paper to
this email for your
convenience. On Problem 5, 653-29 = 624 not 622. He was correct by figuring
out that he should
use "623+1" instead of "623-1" as instructed by the problem (wrong direction
was given for that
problem). Since other kids might have done the same, I would like to bring
this to your attention
so that the kids can know which way is correct.
My second email:
653- 29 = 624 not 622.
Teacher's Response:
The objective is to use mental math and change place value to the nearest
ten in order to do so, not subtract 29 from 653. This was taught within our
class extensively and aligns to the ** State Learning Standard 4.NBT.4
which states: The student will add and subtract multi-digit whole numbers
using the standard algorithm. The strategy being taught in this section is
to mentally add or subtract larger numbers, by taking and giving to make one
number end in a ten, hundred or thousand.
Not being within the lesson, it may be hard to see what the students are
asked to know. I would love to meet with you sometime to show you what the
expectation was for this assignment and a little bit about this curriculum. |
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