女儿家庭作业难倒一家人 Daughter homework beats family

　　原本想好好利用元旦三天休息的张秀凤，却因为在杨家坪小学读四年级的女儿拿回的一道家庭作业郁闷。张秀凤将难倒他们一家的作业拿给了记者看，当记者读完题后也认为该题有难度。原来这道题为：一列队伍长100米正在行进，传令兵从排尾走到排头，又从排头走到排尾，这列队伍正好前进了100米，已知队伍的速度和传令兵的速度保持不变!问传令兵走了多少米?

Originally wanted to take advantage of New Year's day three days rest ZhangXiuFeng,But because in yangjiaping read primary school grade four's daughter back a homework.ZhangXiuFeng beat them showed a reporter a homework,As a reporter after reading the topic also think this question has difficulty.Was on the way:A column WuChang is 100 meters,Messenger from PaiWei went to the market,And from top to PaiWei,This team is just ahead of the 100 m,Known team's speed and the speed of the messenger remain unchanged!Ask the messenger how many meters away?

　　“我和老公想了一天一夜都没能解答出来，于是在2号将题拿给了姐姐的孩子做。”张秀凤告诉记者，她姐姐的儿子在读大学本科。可是，她姐姐的儿子也未能将题解答出来，就连他身边的其他大学生也未能解答出来。“我听到这样的结果时有些生气，觉得老师是乱在布置作业，这样的题连大学生都做不出来，更何况是小学四年级的学生。”

"My husband and I want to a day and a night didn't can solve it out,So in # 2 will be subject to the sister's children."ZhangXiuFeng told reporters,Her sister's son is reading university undergraduate course.but,Her sister's son also failed to question answer,Even he nearby of the other students are unable to answer."When I heard the result some angry,Think the teacher is in homework,This topic even college students do not to come out,What is the fourth grade students."

原来被网上列为“难题” Turned out to be listed online"Difficult problem"

　　为了能将这道家庭作业做出来，张秀凤姐姐的儿子将题输入百度，结果发现此题是网络上一道比较红的难题，曾经难住30个参与解题的大学生。原来这道题有两种解答的方法，第一种方法是利用方程来解答，而第二种方法则是利用极限分析法。

In order to put the homework to do,ZhangXiuFeng sister son will question enter baidu,Found this problem is a difficult problem that is red on the network,Once so 30 college students to participate in problem solving.So there are two ways to answer to this question,The first method is to use equations to solve,And the second method is using the limit analysis method.

　　张秀凤认为，才念小学四年级的孩子没有必要做这么难的题，同时也打击孩子和家长的信心，为他们增添了烦恼。

ZhangXiuFeng think,Just read primary school grade four of children don't have to do such a difficult problem,At the same time also blow the confidence of the children and their parents,Added a trouble for them.

老师：让孩子体会思考的快乐 The teacher:Let the child experience the joy of thinking

　　这么难的题怎么会布置给孩子们当家庭作业呢？记者联系上了布置此题的老师。该老师表示，这道题是他无意间在网上发现的，觉得很有意思就布置给孩子当元旦里的家庭作业。“这道题的难度肯定超出了孩子们所学的范围，但是这样的题却能培养孩子们的推理能力。”老师表示，虽然网上给出的解答十分复杂，但是可能有孩子逻辑推理能力很好的，会根据自己的方法得出答案。并且这道题并没有要孩子一定做出来，做不出来也不会批评孩子。主要是希望孩子们能动脑筋去思考，体会思考过程中的快乐。

Such a difficult problem how to decorate for the children when homework?The reporter contact on the layout this teacher.The teacher said,The problem is he accidentally found on the Internet,Feel very interesting and arrangement for the child when his homework in the New Year's day."The difficulty of this problem is certainly beyond the scope of the children what they have learned,But the problem is to cultivate the children's reasoning ability."The teacher said,Although the solution given in online is very complicated,But is likely to have children very good logical reasoning ability,Will according to your own way get the answer.And the problem did not have a child must be done,Children do not to come out will not criticism.Is mainly hope children can use to think about,Feel the happiness in the process of thinking.

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这道题是如何解出来的？ The problem is how to solve it?

　　题目：一列队伍长100米正在行进，传令兵从排尾走到排头，又从排头走到排尾，这列队伍正好前进了100米，已知队伍的速度和传令兵的速度保持不变!问传令兵走了多少米?

The topic:A column WuChang is 100 meters,Messenger from PaiWei went to the market,And from top to PaiWei,This team is just ahead of the 100 m,Known team's speed and the speed of the messenger remain unchanged!Ask the messenger how many meters away?

　　A.100米

A. 100 meters

　　B.200米

B. 200 meters

　　C.300米

C. 300 meters

　　D.100+100*2米

D. 100 + 100 * 2 m

　　E.150米

E. 150 meters

　　F.170.71米

F. 170.71 meters

　　答案：D.100+100*2米

The answer:D. 100 + 100 * 2 m

　　两位网友的解题过程：

Two users of the problem solving process:

　　方法一：先假定排头兵的速度是V1，队伍的速度是V2,另外，排头兵从排尾走到排头的路程应该比队伍长，比队伍长的这部分假定为X,这时排头兵开始返回走并走到队伍的排尾也就是开始走时的排头，不难发现他返回走的路程长度也是X,那么根据这两个时间段我们可以得到两个方程式：

Method a:Presuppose that contribute to the speed is V1,The speed of the team is V2,In addition,Contribute to go to the top journey from PaiWei should be longer than the team,Than this part of the team long assumed to X,The world began returning to walk and walk to the team PaiWei is when the start of the market,It is not hard to find his () function returns the length's journey is X,So according to this two time we can get the equation:

　　100+X/V1=X/V2

100 + = X/X/V1 V2

　　X/V1=100-X/V2

X/V1 = 100 - X/V2

　　推出V1/V2=100+X/X=X/100-X

Launch V1 and V2 = + X/X = X / 100-100 X

　　推出X=5000的平方根

Out of the square root of X = 5000

　　那么他走的路程=100+2*5000的平方根，答案D是正确的。确实不应该是一道小学题

So he's journey = 100 + 2 * the square root of 5000,D the answer is correct.It should not be a primary school

　　方法二：极限分析法。假设队伍不前进，传令兵从排头往回走到排尾，走的路程是100+100=200米，再假设队伍走了100米，传令兵才出发，从排头往回走到排尾，走的路程100+100+100=300米，因为是同时前进，所以200米

Method 2:Limit analysis method.Assumes that the team does not forward,The messenger from the top to go back to the PaiWei,'s journey is 100 + 100 = 200 m,To assume team walked 100 meters,The messenger to start,From top to go back to PaiWei,'s journey 100 + 100 + 100 = 300 m,Because it is at the same time,So 200 meters

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超出可接受难度，会让孩子逐渐丧失兴趣 Beyond the acceptable degree of difficulty,Can let the child losing interest

　　沙坪坝区新桥小学从事十多年小学数学教学的刘老师表示，小学生阶段的作业不应该太难，只要合适就行，老师一般会根据学生各个阶段的教学内容，偶尔在家庭作业中穿插一两道让学生开动脑筋的智力题，培养学生的探索发现能力。但无论是哪个年龄段的教育，都应坚持“适龄教育”。如果超出学生年龄段可接受的难度，会让孩子逐渐丧失学习兴趣，这样对小学生的成长是弊大于利。同时，家长们对于一些怪题、偏题，要正确对待。（华龙网-重庆商报记者 刘雨露）

Shapingba district xinqiao engaged in more than ten years of elementary school mathematics teaching of primary school teacher liu said,Primary school stage of the work should not be too difficult,As long as appropriate,The teacher usually all phases of the teaching contents according to the students,Occasionally in the homework with the intelligence of a two way to let the students' brains,Develop the students' ability of discovery.But regardless of which age education,Should adhere to the"School-age education".If beyond the difficulty of the student age is acceptable,Can let the child gradually lose interest in learning,So on the growth of primary school students do more harm than good.At the same time,Parents to some strange questions/A tricky question,To treat correctly.(China registered - chongqing business newspaper reporter liu dew or rain)