Tisch
Teaching objective: 1. Understand the music score, understand the meaning of the music score, read the music score correctly, write the music score, and master the names of each part of the music score.
2. We can use fractions to understand "divide a whole into several parts on average, indicating the number of parts".
3. Cultivate students' observation, imagination and practical ability.
Teaching focus:
Understand the meaning of the average score, understand the meaning of the score.
Teaching difficulties:
The more copies you correctly distinguish, the less copies you get.
Teaching process:
First, contact life, create a situation, and draw from the average score 1/2.
1, class, how about a game before class today? Then please pay attention and listen carefully to see who responds quickly!
(1) 4 apples, distributed to 2 people on average. How many apples does everyone have?
(2) There are two apples, which are distributed to two people equally. How many apples does everyone have?
(3) There is only one apple now, or two people share it equally. How many can each person take?
Divide an apple equally to two people, and each person will share half. What should I say about that half? Students, can you express half an apple in your favorite way? You can draw pictures and write Chinese characters. )
Student: Act on the blackboard and give a brief introduction.
Teacher: Students express half of the apples in their favorite way. Your methods are all very good. Which method do you think is better? When an apple is divided into two parts on average, it can be represented by this number 1/2 like this classmate. "
Do you know what this number is called?
This is the new friend we are going to meet today-Score. (blackboard writing: recognition score)
Second, the specific meaning of experience half.
1, teacher: (showing physical graphics) Look, now I have an apple in my hand. How can I get half of it? (cut)
But now the teacher has a picture of an apple, how can you get half of it?
Teacher: Why is it folded in half?
Teacher: Yes, after being folded in half, the two parts completely overlap, which means the score is average. (Don't say symmetry)
(Post half an apple picture)
Teacher: We divide an apple into two parts, one of which is half of this apple.
Say it. Divide an apple into two parts, one of which is half of the apple (talk to 3 or 4 students)
Teacher: What about the other half of the apple?
It is also half of this apple. Why?
Summary: (We divide this apple into two parts equally. This is one part, half of this apple, and this is another part, half of this apple. These two parts add up to this apple. ) whisper.
2. Find someone else to talk about the meaning of half.
Teacher: We just divided an apple into two parts, and each part is half of it. This is a rectangular piece of paper. Can you get half? Requirements: Take out a rectangular piece of paper and fold it in half.
Teacher: (Sticking the work on the blackboard) The student said: How did you fold it? How did you get half of the rectangle?
He pointed to the blackboard and said, Look, these rectangles are of different sizes and folded in different ways. There are apples here. Why can some be represented by half?
Teacher: Summary: It seems that no matter whether it is an apple or a rectangle, as long as it is divided into two parts on average, one part is half of it.
4. Verify pizza: Why can't it be represented by half?
5. Understand that graphics with the same shape but different sizes can be represented by half (Xiuyuan Courseware).
6. Understand that graphics with different shapes and the same size can be expressed in half (show square courseware)
7. Judge and further understand the "average score"
Third, understand other scores and write them in the exploration experience.
1, we learned half of it together, now let's get to know one third together.
Show courseware: divide a cake into three parts on average, each part is one third of it. Write: write the fractional line first, the denominator of the fractional line, and finally the numerator of the number of copies.
2. Now think quietly: What do "3" and "1" mean? Do you know what the horizontal line in the middle of the score means? (Discuss at the same table) 3 is divided into three parts on average, called denominator, 1 is a part of these three parts, called numerator, and the horizontal line in the middle is the average score, called fractional line. (equivalent to the division symbol in division)
3, the book is empty: write one-third on the table by hand.
Can you fold a square piece of paper and show a quarter of it in shadow? See who has more methods?
Teacher: (collecting different works for blackboard display) There is feedback. Who folded it like this? statistics
Teacher: Can they all be expressed in a quarter? (individual teachers need to verify, and teachers who are difficult and have not folded will show one. )
Teacher: You are great. There are so many different folds on a square piece of paper that you can get a quarter of it.
In fact, except for the scores in the graphs, they are everywhere around us. There are 36 students in our class. How many people are there in our class? ( 1/36)
If there is a big cake, Liu Yujia's team will share the cake equally, and everyone will get the cake? (blackboard: 1/6)
If the girls share the cake equally, will everyone share the cake? (blackboard:115)
If the whole class shares this piece equally, everyone will get this cake? (blackboard: 1/36)
Thinking: What did you find about these scores? The more copies you get, the less you get.
6. Do you still want to know those scores? Can you give an example of your own score?
Teacher: Can you finish like this?
Health: By the way, the number of fractions is infinite.
Fourth, feel the mathematical culture.
1, Introduction to the History of Fraction Development
It's amazing that the students have created so many scores. In fact, China is the first country to use fractions, which is earlier than the west 1000 years!
We have just studied music scores together, so what do you know about music scores now?
Verb (abbreviation for verb) consolidation exercise
1, the students are really amazing. They have so much understanding of fractions. Then look at these pictures. Can you use fractions to represent the colored parts in the pictures? (fraction, fraction)
2. Looking at the picture, how much part of the rectangle does the shadow part occupy? (courseware verification)
Contrast: one-half, one-third and one-sixth. What did you find?
Lingling and Tintin are arguing endlessly. Why?
Divide a ham sausage into two parts, one of which must be half of this ham sausage?
4. Show courseware: Are triangles with different shapes and invisible sizes still average?
Question: There are 6 students in the first group of our class. Divide them equally into two parts. What's the score for each part? How many people are there in each serving?
Sixth, sum up the harvest
This class is coming to an end. Can you tell me what you got or learned?
Blackboard design:
A preliminary understanding of scores
extreme
The objectives of this lesson are:
1. Experience average score; A small part of the initial understanding.
2. The fractional size of the comparative molecule is 1.
3. Cultivate students' mathematical autonomous learning ability and mathematical thinking ability through hands-on operation, observation and comparison.
Teaching process:
First, through the understanding of "half", understand the meaning of "half"
1. How much is half?
(1) Half a class.
(2) Half of a group of students
(3) Half a circle
2. How to divide the half? (divided into two equal parts on average, the two are divided into two)
Everything can be divided into two halves, which number is used to represent this half?
For example, half of the classes are represented by 20 people, and half of a group of students are represented by 5 people. We can tell how big it is: in real life, we often encounter this semi-circular situation, and we can't tell how big it is with the numbers we have learned. So I introduced a math score, as this classmate said just now, you can use half, and this score represents half of a circle. Half of everything can be represented by 1/2.
4. Fold in half and fold in half: fold in half on the square paper and color it.
Second, hands-on operation, understand a quarter.
1. Can you fold half and quarter?
2. Folding and coloring means a quarter, communication.
After students have a preliminary understanding of one-half, they feel comfortable to fold one-quarter. )
3. Different folding methods have different shapes. Why can everything be represented by 1/4?
Through this discount, students can understand that as long as they are divided into four parts on average, one of them is a quarter.
3. Discrimination: Which numbers can be expressed by one quarter, and explain the reasons.
3. Comparison with the fraction of molecule 1
1. I've given you a quarter discount. Can I get a discount? Can you take one as a score?
Students got 1/8,116, 1/32, and so on. They are very excited to get new scores through their own operations.
With so many scores, who do you think scored the most?
Most students think that one-thirty-two is the smallest, and give the reason: 32 is greater than 8, of course, 1/32 is greater. Some students found that the discount was getting smaller and smaller, and thought that 1/32 was the smallest. At this time, the teacher didn't say anything. )
4. Story:
Pigs and pigs divide watermelons: On one occasion, the Tang Priest sent pigs and pigs to explore the road and never came back for a long time. So he sent the Monkey King to find it. It turns out that Pig Bajie is eating watermelon happily. As soon as the first bite was taken, Wukong fell from the sky. The Monkey King said, "I eat half a watermelon." Pigs always want to eat more. He said happily, "I want to eat one eighth." At this time, the students are talking. Who eats more? Now most students think that the Monkey King eats too much because he ate half a watermelon. Some people think that Pig has eaten too much.
Courseware demonstration: divide watermelons (through visual demonstration: everyone agrees that one-eighth is smaller than one-half. The students found that the more the average number of copies, the smaller their share. )
5. Back to the comparison of scores in origami, 1/8 and 1/32. At this time, the students all laughed. It turns out that students can't compare scores directly with the comparison of 32 and 8, and their understanding has improved. Understand that the larger the denominator, the more the average number of copies, the smaller.
Four, practice using (omitted)
Tisso
First, the design ideas:
Find the "nearest development zone" where students learn new knowledge and know the score in the big background. At the same time, strengthen intuitive teaching and reduce cognitive difficulty. Create interesting question situations according to the age characteristics of students.
Second, the analysis of learning situation:
The initial understanding of fractions is based on the fact that students have mastered some integer knowledge, mainly to let students understand the meaning of fractions. This is the first time that students are exposed to scores. It is a qualitative leap for students to understand the concept of numbers from integers to fractions, because there are great differences in meaning, reading, writing methods and calculation methods. The concept of score is abstract, so it is difficult for students to accept it at one time and learn it well. Therefore, the knowledge of fractions is taught in stages, and this unit is only a "preliminary understanding". Cognitive score is the first stage of cognitive score, the "core" of the unit and the initial course of the whole unit, which plays a vital role in future study. Therefore, we should use some familiar figures and concrete examples to help students gradually form a correct representation of the score and establish a preliminary concept of the score through demonstration and operation.
Third, the teaching objectives:
(A) cognitive goals
1, by creating a certain learning situation, guide students to explore familiar life cases and intuitive graphics, so that students can initially understand a score, establish a preliminary concept of a score, and can read and write a score.
2. The molecular fraction of 1 can be compared.
(2) Ability goal
1. Cultivate students' cooperative consciousness, mathematical thinking and language expression ability through group cooperative learning activities.
2. Cultivate students' observation and analysis ability and hands-on operation ability, so as to develop students' thinking.
(3) Emotional goals
1, so that students can gain positive emotional experience in the process of discussion and exchange, and develop their awareness of exploration and innovation.
2. In observation, comparison and hands-on operation, cultivate students' spirit of being brave in exploration and independent learning, perceive that mathematics comes from and is used in life, have a sense of intimacy with mathematics, and gain a successful experience of using knowledge to solve problems.
Fourth, the key points and difficulties:
Teaching emphasis: establish the score of representation. Teaching difficulties: a preliminary understanding of the meaning of denominator and molecular representation.
Five, teaching strategies and means:
In the teaching of this class, we should pay full attention to students' operation of learning tools, and let students have an intuitive understanding of the meaning of fractions through origami, so that students can deepen their understanding of the meaning of fractions and reduce the difficulty of understanding the concept of fractions. Especially when the score of the comparative molecule is 1, the process of dividing watermelon by Pig Bajie is shown on a disk, and students intuitively realize that the more copies, the smaller. Therefore, students internalize the knowledge that molecules are the comparison of scores. At the same time, according to the age characteristics of students, create interesting problem situations.
Six, preparation before class:
1, students prepare: rectangular, square and round pieces of paper, scissors.
2. Teachers' teaching preparation: Before class, learn about students' familiarity with scores.
3. Design and layout of teaching environment: prepare some small magnets on the blackboard.
4. Design and preparation of teaching tools: several rectangular, square and circular pieces of paper and a pair of scissors. Two moon cake pictures.
Seven, the teaching process:
(A) the creation of situations, the introduction of new courses
Students, today the teacher will tell you a story from Journey to the West.
It is said that Tang Priest and his disciples traveled thousands of miles to the West to learn from the scriptures. On this day, they came to a market town and saw someone carrying moon cakes on the road, only to remember that today is the Mid-Autumn Festival. At this moment, I happened to pass by a moon cake shop. "Wow, so many moon cakes!" "Eight quit soon saw all kinds of moon cakes in the store, and his mouth was watering. He kept saying, "Master, I want to eat moon cakes. "But the Tang Priest said," You can eat moon cakes if you want, but I have to test you first. The Tang Priest said, "There are four moon cakes. You and Wukong share them equally." How much is each? Please write down this number. "Pig eight quit to write down this number. The Tang Priest added, "There are two mooncakes, which you and Wukong share equally. How much will each person share? Please write down this number. " Pig Bajie thought about it and wrote down the number. Seeing Pig's quick reaction, the Tang Priest said, "Well, if there is only one moon cake, how many pieces will you and Wukong share equally? How to write? " This really stumped Bajie.
Students, do you know how much each person will get? (Some people say that everyone is divided into half, while others say that everyone is divided into half. What number can a half moon cake represent? The students don't seem to know what numbers to use. It doesn't matter. Today, the teacher specially invited a new friend to help us solve this problem. Yes-scores. In this lesson, let's learn the preliminary understanding of fractions together. (Show the topic) The first network of the new curriculum standard
[Design Description: Thinking begins with asking questions, and curiosity is the nature of children and the starting point for students to explore the unknown world. According to the characteristics of primary school students' love to tell stories, creating problem situations from stories not only naturally shows the necessity of learning scores (because they can't be solved by integers, they need fractions), but also promotes students' awareness of inquiry. ]
(B) hands-on practice, independent inquiry
Know half.
(1) Guess: If a moon cake is divided into two parts on average, how can one part be expressed as a fraction?
Teacher: Divide a circle into two parts, and half is one of the two parts, that is, half of the circle. Write: 1/2. What does "2" mean by combining moon cake pictures in books? What does "1" mean?
(2) Teacher's Note: 2 means the average number of copies, and 1 means one of them.
(3) Hands-on practice
A, fold a fold: let students use various pieces of paper to fold 1/2, (round, rectangular, square).
Show students several typical folding methods.
C, highlight the thinking process from the operation process.
Teacher: All these different shapes of paper can be folded into its 1/2. Think about it. The shape of the same piece of paper is different. Why can everything be represented by 1/2?
(4) Understand the importance of average score in discrimination.
Fold out several kinds that are not evenly divided. Think about it. Can it be expressed in half? (Re-emphasize the average score)
[Design Description: Through intuitive deduction of the thinking development process contained in mathematical knowledge, students can experience self-digestion. Teachers do not directly tell students ready-made conclusions, nor do they arrange students' thinking patterns and processes. Instead, it drives students' inner thinking vitality through "overlapping" and realizes the connotation and importance of "average score", so that students' thinking mode is not rigid and unconventional, and their thinking realizes leap-forward development. ]
Know quarters.
(1) observation and reasoning
Teacher: Let's think about it. If a moon cake is divided into four parts on average, how much is each part?
(2) Carry out activities with preferential treatment of 1/4.
A, Teacher: What should I do to get 1/4 of a graph? Fold a round piece of paper and show a quarter with a shaded part.
B. Report: How did you get 1/4? What does 1/4 mean?
C, let the students take out the square paper with the same size, fold it into different 1/4 colors in groups and stick it on the floor, and see which group folds the most.
D. how to fold the report. Q: Is this 1/4 part the same size? Why?
Important: If the overall size is the same, its 1/4 size is the same.
Know a little.
(1) We already know 1/2 and 1/4 just now. We call these numbers fractions. Do you remember any other scores? Students' answers on the blackboard. (Write a few scores with larger denominator consciously) Take a few and talk about the meaning of the scores.
(2) looking for. (Show the theme map)
Please observe carefully. What are the children doing in the amusement park? Where did you find the score? Why?
(3) Exercise: Do the problem 1.
[Design Description: Based on 1/2, 1/4 learning will enable students to feel, analyze and solve new problems themselves, learn to associate new knowledge and life experience with existing knowledge and experience, learn to understand knowledge through hands-on operation and practice, and learn to draw inferences from others and make innovations. ]
Reproduce the scene and compare the sizes.
(1) The story raises questions.
Teacher: Next, the teacher went on to tell the story of Journey to the West. Tang priest and his disciples bought some moon cakes at the moon cake shop and continued on their way. They walked, it was already noon, and the pig's stomach was growling with hunger. At this time, the Tang Priest took out a new cake and gave it to Bajie and the Monkey King, saying that he would give it to the Monkey King 1/4 and Pig 1/2. Pig bajie said loudly in a hurry, no, no, I have a big belly. I want to eat a big one. I want to eat 1/4 Students, did the pig get a big bargain and get a big piece? (blackboard writing 1/2 1/4)
(2) Solve the problem:
Let the students think and speak.
Teacher: What do you think? Why do most people eat 1/2 and few people eat 1/4?
Can you use the wafer in your hand instead of the cake to verify it?
Feedback, please tell two students how to verify.
Summary: The original score also has a size. 1/2 means that an object is divided into two parts on average, and one part is larger than the one divided into four parts, so 1/2 > 1/4.
(3) Extension:
First, at this time, the sand monk also came to eat. He said he would eat the moon cake 1/8. Which of them do you think eats the most and who eats the least?
B, look at the blackboard, can you still compare these scores? Choose two numbers and compare them according to the students' answers. What did you find? (The more copies, the smaller) Which of these scores is the smallest?
(4) Exercise: Do the second question.
[Design Description: Thirdly, the story-telling method leads to the comparison of scores, so that students can find the correct answer by solving the problems in the story. At the same time, the story also contains the correct answer, and the comparison of scores is closely related to real life, so it is not difficult for students to find the correct answer. And once again use wafer instead of moon cakes to prove and verify the answer. ]
(D) Talk about it and make a class summary.
Tell me what you know about fractions.
Think about what the two numbers in the score mean. Is there a clear distinction?