《分數(shù)的意義》教學(xué)設(shè)計及反思

1、分數(shù)的意義教學(xué)設(shè)計及反思（Teaching design and Reflectionon the significance of fraction）Teaching design and Reflectionon the significanceof fractionYishui third experimental primary school Qiu MeizhiFirst, expand the meaning of 1/4(a) a plurality of objects from one object to the1. do you know the score of 1/4?

2、Can you give me an example, what is the 1/4?1: take one of the moon cakes were divided into 4 parts, one of which is that it's 1/4It's nice to think of moon cakes. What's the average size ofa mooncake? Can 1 of them be expressed in 1/4? 4 Well, is there any example of that? Who can say o

3、ne more 1/4?2: a cake were divided into 4 parts, of which 1 copies of its 1/4Who else would like to talk about?3: put some books were divided into 4 parts, each of which is 1/4.Well, the student said differently. He divided 4 parts, each of which was 1/4 of them. Agreed? Issome books into there anyt

4、hingelse? Raw 4:?.Strange, all things are obviously not the same, how 1/4 can be used to express?Student: because all of them were divided into 4 parts, one of which is 1/4.Originally, can be expressed in 1/4, and what is Never mind?2., there seems to be a lot of 1/4 in life. The teacher also brings

5、 one thing and wants to know what it is. Look at the picture. 1 applesThis apple, the average distribution to four people, each person's share, can be used to express 1/4?Sheng: energyAgree with him? Well, to see, in figure (a lot of Apple)There are so many apples, which are equally distributed

6、to four people. Can each person be represented by 1/4?Some students said yes, some students said no.Let's do try. The teacher prepared some wafer for everyone, installed in your group envelope. Together with the group of four students, and use it to replace the apple, the actualpoints. Nowthink,

7、 these apples equally among the four of you, each share, what can not be used 1/4 to express.Manual operation.Well, the students were very cooperative. All have their ownideas? Who's going totalkabout it? How manyapplesare therein your group? (Book: 8) do you think that the averagedistributionof

8、 8 apples to 4 people,each person'sshare,butalso can be used to express 1/4?Sheng: energyWell,I put down your group. Conclusionthe other group is what?Is it 8 apples?Student: we are 12 apples components. Each of the 3, 1/4 can be used to expressThat's true. Do you have any questions?Is there

9、 any other difference? Writing: 12 apples, 16 apples, 20 applesDo you have any questions? There is something wrong with the teacher. Our apples are obviously different, 8, 12, 16, and so on. Why can anyone use 1/4?Student: because all of them divided into 4.That's great! So, can with 1/4 If ther

10、e are 200 apples, averagepoints, to 4and how muchthe stuff? people, each person can,can also be used?(two) cognition unit "1""1. looking back, when we were studying 1/4, we actually looked at 1 apples and manyof these apples as a whole. As long as this will be a whole how you can get

11、it, 1/4? In fact, when we study other fractions, we often need to think of such an object, ormany objects, as a whole. 1 apples can be considered as a whole, 8 apples can be regarded as a whole, 16 apples? How about 21?In mathematics, people often use natural number 1 to represent a whole, which is

12、customarily called unit 12. think,besides justthe teacherfound that,look around us,In our life, what else do you think can be regarded as a whole, that is, unit 1?Sheng.Is it possible? This example can be found in life?(three) re understanding 3/5.In addition to that, the teacher also brought some p

13、ictures, see you know?Figure: a round. A round can be regarded as 1 units? Look, ameter can be regarded as 1 units? What about the 5 little rabbits? Think of the whole of a circle, a cup of tea and many flowers as unit 1. What's the number of parentheses in the bracketsbelow? 3/5You see? I see,

14、but I have a problem here:1 unitsof the same?Why are a part of the 3/5 can be used to express?Student: because they are the object of average divided into three parts, that is 2 of them.Great discovery. Althoughthe 1 are not the same, butthey arewhat? So you can use a commonfractionwho said? That is

15、 to say,you can use 3/5 to say, with the unit 1 is what Never mind?Two. Recognize other scores1. through learning, we have recognized the unit 1, the meaning of 1/4 and 3/5 also have a more profound understanding. Look, the teacher also brings scores. What do they mean? (pictures)do you know? Whokno

16、ws the score indicatesthe meaning of what?The teacher gave each of the studentsto prepare somematerials,there are many objects in a circle, there is a rectangular or square. You can combine the hands of the material, choose a score here, to divide, fold, and slash a fraction of what you most want to

17、 say it?2. hands start operation.3. What students have completed their work? Please look at your work on it, I take what as 1 units, divided into several pieces, said a few of the painting?Which fraction do you mean?Sheng:.OK？ Ihave a suggestion,before and afterthe group of 4 people,let's say: I

18、 put in the group.The teacher also collected several students' works, can you quickly see what he is a few points? Show. These works are the same as unit 1? Why can be used to express it?Sheng:.This is the meaning of 2/3. In the same way to exchange the other two points.Three, said the scores on

19、 the axis1.,the meaning of these scores,we have a deeper understanding.Think about it, just now we mentioned so many units of 1, canyou take such a linesegment is also considered as unit1? FigureFrom 0 to 1 a so long as 1 units, 1/4 said what? Sheng:.Teacher's diagram. 1/4 means that from 0 to t

20、his, so long, and sometimes we just use this point to represent 1/4. From 0 to 1 in this section, we find the 1/4 position, the 2/4?Wehave also found the 2. said 2/3 in this line? Try it yourself, draw a picture, find.Raw operation. Okay? Say, how do you look for it? The teacherrefers to the screen.

21、 Look closely at the screen and yourhomework paper. You think the position of the 2/5 you found is very accurate. Raise your hand!3. just now we have a lot of marks on the line from 0 to 1. Apart from a few of them, are there any other scores between 0 and 1? Then, then down to, between 1 and 2, the

22、re is no score?Between 2 and 3?You're right 。 In fact, in the middle of these integers, lots of fractions are dotted, and fractions, like integers, are a new number.Four, summarize the significance of fractionsWe have further understanding of the scores, the teacher also brought some small exerc

23、ises, you want to test,Look who's the quickest, okay? Please look at the picture below, represents a fraction of a few?Sheng:.The teacher asked: this picture since they said one-third of the number, why color star is different? Student: because the total number is differentThat is, unit 1 is dif

24、ferent. Is this? It is what it is really important to unit 1.Re drawing.Is this the same as unit 1? Why show scores but not the same?So, in order to accurately represent a score, we must payattention to what the unit 1 is, and what should we pay attention to? The average number of copies of the book

25、, said the number of copies. The meaning of it, points out.Five, expand the application1. through the study, the understanding of the score a step further. In our real life, you have seen scores?The teacher collected such a: Show: according to statistics, primary school students in our country myopi

26、a accounted for about 1/5 of the total number of people.You must know the meaning of 1/5. Who said.What do you think? Sheng:.Everyone from the 1/5 of the fraction of only occurs this feeling. It seems a small fraction can offer us a lot ofinformation. Howmany myopic students are there in our school?

27、 Hands up, please. What fraction of our students myopia is appropriate? It looks like the situation is not optimistic. What do you think we should do?2. See a data (shown: a map of the world)An estimateof the totalland area of about the area of the earth()?The teacher provides two scores, one of two

28、, which is your choice? Why? What about the ocean area?3, the boys in our class accounted for the number of the wholeclass, which means(1) as the unit, the average is divided into (), boys accounted for ()Six, summaryIn this class, we walked back to the score and understood the significance of the s

29、core. I hope everyone out of the classroom into life, can find more marks, to learn more about the score knowledge!Blackboard writing design:Significance of fraction18 said the number of copies12 units, 116 of the average number of copiesReflections on teaching:In April8th I participatedin the Linyi

30、MunicipalOrganizationDepartment of the construction of "high class" activities, in just one day time is listening to four class, our school is"constructingefficientclassroom"activitiesafterthe end ofthe study, the first step is to listen to the class, school leaders want to show

31、me a class. Listen to the review of the four class, relatively deep impression is Linshu education school teacher Lv Jian taught the meaning of "score", feeling teaching ideas in this class teacher Lu design is relativelyclear, teachingis relatively compact, thestudents'learningeffect

32、is relatively good, so come back to me about try to imitate it. See if you can make the same effect.But now I teach is the fourth grade 2, and the meaning of "score" is the fifth grade 2 content Xinlimeidi, first feel the studentshave the basic knowledge is not very understanding, then the

33、 feeling of this class is a concept of teaching, students need to experience, may be harder in some when the lecture. But looking back to teacher Lu's wonderful class, estimated that the difficulty of this class should not be very big, so I took the attitude of trying to choose this lesson.In a

34、formal class before I had a trial, the effect is very not ideal, feel confused,Students' enthusiasm for learning is not high. After thelectureI reviewed, thereasons for the failure of thestudentsis not, but because he wasn't prepared enough, on the wholeteaching process can not grasp. Once t

35、hought about anothertopic, but because the timeis tight,hard on the scalpspeak.I made full preparation, re combing the teaching process,adjustteaching ideas, making teachingaids carefullytolearn,after feeling very tired, following the class to talkitis also not easy teaching design, a little bit abo

36、ut my experiences:Advantage：(1)teachingideas arerelativelyclear.By dividingan objectintoseveralobjects,it expands themeaning of 1/4,thusleadsto the concept of unit"1",which notonlyrepresentsan object,but also can represent many objects. On the basis of a morein-depth understandingofthe 3/5

37、meanings, and know theotherscores, with the further understanding of the axis fraction;based on a large number of perceptual experience to abstractthe meaning of scores, role comprehension scores in life.(2) the teaching situation is close to the actual life of students. At the beginning of the clas

38、s, through the conversation, let the students lift the examples in life, say what is 1/4? And then use the more familiar picture apple, toexpand the meaning of 1/4 and the unit "1" understanding. Reallifepracticein the consolidation stage setting is relativelyclosetothestudents,thenumber o

39、f myopia;landarea accountfor a fraction of the total area of the earth a few; the boysand girlsaccounted fora totalnumber of theclassof teachingscenariosare more familiarwiththe students,thestudents aremore interested in the teaching scene, so the whole class students interested in higher, better cl

40、assroom atmosphere, students master the teaching content is also good.(3) the teaching content is based on the students' cognitive level. It is pointed out in the curriculum standard that the teacher's teaching should be based on the students' cognitivelevel and the existing experience,

41、and face all the students.In this lesson, considering the students in the third grade when have a preliminary understanding of scores, understood thescore is one object is divided into a number of copies, said one or few copies; so the emphasis of class teaching on thesystem comprehensively summariz

42、ed the meaning of scores on the score, that is, by an object into multiple objects, expand and generalize the meaning of scores.Insufficiency:(1) theteachingdesign isnot reasonableenough. The teachingdesign isused for the teacherLu, I havenothing inside, feelstiff, somewhat rigidly inflexible. Treatment of studentsreporting and some exercises are too divided by the act