2022年《分数的意义》教学设计及反思 .pdf
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1、分数的意义教学设计及反思(Teaching design and Reflection on the significance of fraction)Teaching design and Reflection on the significance of fraction Yishui third experimental primary school Qiu Meizhi First, expand the meaning of 1/4 (a) a plurality of objects from one object to the 1. do you know the score o
2、f 1/4? 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 its 1/4 Its nice to think of moon cakes. Whats the average size of a mooncake? Can 1 of them be expressed in 1/4? 4 Well, is there any example of that? Who can say one mo
3、re 1/4? 2: a cake were divided into 4 parts, of which 1 copies of its 1/4 Who 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 some books into 4 parts, each of which was 1/4 of them. Agreed? Is there anyt
4、hing 名师归纳总结 精品学习资料 - - - - - - - - - - - - - - -精心整理归纳 精选学习资料 - - - - - - - - - - - - - - - 第 1 页,共 13 页 - - - - - - - - - else? 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. Origi
5、nally, 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 one thing and wants to know what it is. Look at the picture. 1 apples This apple, the average distribution to four people, each persons share, can be used to express 1/4? Sheng
6、: energy Agree with him? Well, to see, in figure (a lot of Apple) There are so many apples, which are equally distributed to four people. Can each person be represented by 1/4? Some students said yes, some students said no. Lets do try. The teacher prepared some wafer for everyone, installed in your
7、 group envelope. Together with the group of four students, and use it to replace the apple, the actual points. Now think, these apples equally among the four of you, each share, what can not be used 1/4 to express. 名师归纳总结 精品学习资料 - - - - - - - - - - - - - - -精心整理归纳 精选学习资料 - - - - - - - - - - - - - -
8、- 第 2 页,共 13 页 - - - - - - - - - Manual operation. Well, the students were very cooperative. All have their own ideas? Whos going to talk about it? How many apples are there in your group? (Book: 8) do you think that the average distribution of 8 apples to 4 people, each persons share, but also can
9、be used to express 1/4? Sheng: energy Well, I put down your group. Conclusion the other group is what? Is it 8 apples? Student: we are 12 apples components. Each of the 3, 1/4 can be used to express Thats true. Do you have any questions? Is there any other difference? Writing: 12 apples, 16 apples,
10、20 apples Do 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. Thats great! So, can with 1/4 points, and how much the stuff? If there are 200 apples, averag
11、e to 4 people, each person can, can also be used? 名师归纳总结 精品学习资料 - - - - - - - - - - - - - - -精心整理归纳 精选学习资料 - - - - - - - - - - - - - - - 第 3 页,共 13 页 - - - - - - - - - (two) cognition unit 1 1. looking back, when we were studying 1/4, we actually looked at 1 apples and many of these apples as a whol
12、e. As long as this will be a whole how you can get it, 1/4? In fact, when we study other fractions, we often need to think of such an object, or many 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
13、 use natural number 1 to represent a whole, which is customarily called unit 1 2. think, besides just the teacher found 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 understa
14、nding 3/5. In addition to that, the teacher also brought some pictures, see you know? Figure: a round. A round can be regarded as 1 units? Look, a meter 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. Whats the num
15、ber of parentheses in the brackets 名师归纳总结 精品学习资料 - - - - - - - - - - - - - - -精心整理归纳 精选学习资料 - - - - - - - - - - - - - - - 第 4 页,共 13 页 - - - - - - - - - below? 3/5 You see? I see, but I have a problem here: 1 units of the same? Why are a part of the 3/5 can be used to express? Student: because they
16、are the object of average divided into three parts, that is 2 of them. Great discovery. Although the 1 are not the same, but they are what? So you can use a common fraction who said? That is to say, you can use 3/5 to say, with the unit 1 is what Never mind? Two. Recognize other scores 1. through le
17、arning, 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? Who knows the score indicates the meaning of what? The teacher gave each of the students to prepare some materia
18、ls, 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 say it? 2. hands start operation. 3. What students have completed their work? Please look at your w
19、ork on it, I take what as 1 units, divided into several pieces, said a few of the painting? Which fraction do you mean? 名师归纳总结 精品学习资料 - - - - - - - - - - - - - - -精心整理归纳 精选学习资料 - - - - - - - - - - - - - - - 第 5 页,共 13 页 - - - - - - - - - Sheng:. OK ? I have a suggestion, before and after the group o
20、f 4 people, lets say: I 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. Thr
21、ee, said the scores on the axis 1., the meaning of these scores, we have a deeper understanding. Think about it, just now we mentioned so many units of 1, can you take such a line segment is also considered as unit 1? Figure From 0 to 1 a so long as 1 units, 1/4 said what? Sheng:. Teachers diagram.
22、1/4 means that from 0 to this, 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? We have 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
23、 teacher 名师归纳总结 精品学习资料 - - - - - - - - - - - - - - -精心整理归纳 精选学习资料 - - - - - - - - - - - - - - - 第 6 页,共 13 页 - - - - - - - - - refers to the screen. Look closely at the screen and your homework paper. You think the position of the 2/5 you found is very accurate. Raise your hand! 3. just now we have
24、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, there is no score? Between 2 and 3? Youre right。 In fact, in the middle of these integers, lots of fractions are dotted, and fractions, like integers, ar
25、e a new number. Four, summarize the significance of fractions We have further understanding of the scores, the teacher also brought some small exercises, you want to test, Look whos the quickest, okay? Please look at the picture below, represents a fraction of a few? Sheng:. The teacher asked: this
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