Teaching material analysis:

"Multiplication" is the content in the field of number and algebra, and it is an abstract concept in primary school mathematics teaching. These contents are taught on the basis that students master multiplication in table and understand the meaning of division, which is the basis for further learning about multiples, fractions and proportions. The textbook selects the scene where the teacher leads the students to collect shell specimens at the seaside, taking solving problems as the main line, so that students can understand the meaning of "times" initially through hands-on operation and cooperative communication, establish the concept of "times", communicate the relationship between "times" and "times", and know that how many times one number is another can be calculated by division. In the process of solving problems, cultivate students' observation ability, reasoning ability and transfer ability, and develop students' language expression ability.

Teaching objectives:

1. In specific life situations, through physical demonstration and hands-on operation, let students understand the meaning of "multiple" and know how to solve the problem that one number is a multiple of another by division.

2. When comparing two quantities, communicate the relationship between "as much" and "1 times", and the relationship between "several times" and "times", so that students can initially establish the concept of "times".

3. Cultivate students' observation ability, reasoning ability, migration ability and language expression ability in the process of independent exploration, cooperative communication and problem solving.

4, through the specific life situation experience, let students have an interest in mathematics in the learning process, develop a good habit of being willing to use their brains, and experience the happiness of success.

Teaching focus:

Establish the concept of "multiple" and know how to solve the problem that one number is several times that of another by division.

Teaching difficulties:

Understand the meaning of "times".

Teaching aid preparation:

Multimedia courseware, shell pictures, exercise paper, learning toolbox.

Teaching process:

First, create situations and provide materials.

1, Dialogue: Students, do you like going to the seaside? Today, students of the science and technology group are collecting shell specimens at the seaside. Let's go and see their harvest together! (Show the situation map) After careful observation, what mathematical information did you find? According to this information, what math questions can you ask?

2. Exchange feedback.

Suppose 1: Students may ask questions about sum and difference. Explain the relationship between the sum and difference between two quantities that students have learned before asking us.

Hypothesis 2: Students may ask questions about multiples.

(Note: Presupposition 2 is designed according to the number of times students ask more questions in class. )

3. Dialogue: Jing Wong also raised a question. Let's read together.

The problem of students reading together and the problem of teachers posting.

4. Dialogue: Are there any questions after reading it? Students may ask: What is the era? ) Yes, we have never seen twice as much knowledge before. Today, we will study it together and make friends with the times.

Understanding of the times.

Design intention: It is easy to arouse students' interest in learning, stimulate their enthusiasm for learning and pave the way for the teaching of new courses by taking advantage of the situation that students like to pick up shells at the seaside. Use the problems in the courseware to introduce the new lesson and reveal the theme.

Second, analyze materials and understand concepts.

(a) operation demonstration, a preliminary understanding of the significance of the times.

1, Dialogue: Please look at the question carefully again. What mathematical information is needed to solve this problem? (of life)

2. Swing: Swing out the shells of Wang Ding and Li Fei with the tools in your hand.

Students operate learning tools and teachers patrol for guidance.

Exchange and display.

3. Observation: What is the relationship between the six shells picked up by Li Fei and the three shells picked up by Wang Ding?

Suppose 1: (1) Li Fei picked up three more shells than Wang Ding.

(2) There are three fewer shells found in Wang Ding than in Li Fei.

Hypothesis 2: Li Fei picked up as many shells as two Wang Ding.

Hypothesis 3: Li Fei picked up twice as many shells as Wang Ding. (This is what is generated in class during class. )

4.( 1) The following teaching links are designed according to the preset methods.

Dialogue: Is there any way for us to see at a glance that Li Fei has three more shells than Wang Ding?

Default 1: Draw a vertical line (draw a vertical line behind the three shells of Li Fei and Wang Ding).

Presupposition 2: Divide the number of shells in Li Fei into three parts and three parts.

Tell me: How many parts of Li Fei's artillery shells are there now?

Default: two parts.

Dialogue: (The teacher points to each part) What does this part of Li Fei have to do with the number of shells in Wang Ding? What about this part?

Default: as many.

Default: same.

(2) The following teaching links are designed according to preset 2.

Dialogue: Can you show us that Li Fei picked up as many shells as two Wang Ding did?

Put a pendulum on the blackboard and get one point.

Tell me: How many parts of Li Fei's artillery shells are there now?

Default: two parts.

Dialogue: (The teacher points to each part) What does this part of Li Fei have to do with the number of shells in Wang Ding?

Default: as many.

What about this part?

Default: same.

(3) The following teaching links are designed according to the three presuppositions, namely, classroom generation.

Dialogue: Li Fei has twice as many shells as Wang Ding. how do you know Can you tell us something about it?

Class Generation: The number of shells in Li Fei is two threes, so the number of shells in Li Fei is twice that in Wang Ding.

Dialogue: You are great! You already know what the teacher is going to say in this class in advance. What a child who likes learning!

Talk: Look, students, if Wang Ding's shell number 3 is regarded as 1 3, according to this classmate, are there two 3s in Li Fei's shell number? (Default: Yes)

Dialogue: Then who can come up and point?

Pointing to the blackboard.

5. Description: We regard the three shells found in Wang Ding as replicas, which are 1 3s. There are two 3' s in the number of shell casings picked up by Li Fei.

Summary: There are two 3s in 6, so we say that 6 is twice as big as 3.

6. Talk: Hold out your little finger, circle and talk to the teacher.

Talking to each other in the same place.

7. Dialogue: Now, please set up your learning tools again to see who is the best, so that the teacher can see at a glance that the number of shells in Li Fei is twice that in Wang Ding.

Students put another pendulum and let them show it in front.

Follow-up: why do you want to put it in twos and threes? Whose number is it based on?

Dialogue: How many times did Li Fei pick up shells than Wang Ding? Do you know now? Somebody say something.

(2) Hands-on operation to further understand the significance of the times.

Wang Ding gave his shell to a good friend. How many shells are there in Wang Ding now? (2) So now Li Fei has twice as many shells as Wang Ding?

2. Dialogue: Please use the learning tool in your hand to set it up again. Think before setting. Who should you set according to? How many copies do you want?

Students play on swings, and teachers patrol and guide them.

3. Show communication: How to say it? Follow-up: Why two places?

4. Courseware demonstration: 6 has three 2, and 6 is three times that of 2.

Design Intention: In this link, we should follow children's cognitive rules, create sufficient operation activities for students, put forward requirements before each operation, and let students carry out purposeful operation with questions, and then help students understand the meaning of each operation activity through questions after operation, so that students can initially understand the meaning of "times".

Third, with the help of materials, summarize the concepts.

1. Dialogue: Li Fei is also six conch shells. Why is it three times that of Wang Ding and twice that of Wang Ding?

Students exchange ideas.

2. Review and summary: How do we know the time?

Ways to guide students to sort out cognitive times: swing and turn.

3. Demystifying the topic: By posing, turning around and talking, we know that there are two 3' s in 6, and 6 is twice as much as 3, so the students really made friends with 3.

Design intention: In this link, through observation and comparison, students will find that multiples will change due to the change of comparison standards, initially realize the importance of comparison standards, and further deepen their understanding of multiples.

Fourth, consolidate, expand and apply concepts.

1, circle, fill in and say, and deeply understand the significance of the times.

Students independently complete the content of the homework paper, and then show the communication.

Step 2 solve the problem.

Say: Let's go back to the seaside. Can you still ask the question of time?

Ask questions, and the teacher chooses three of them to answer.

(1) How many times more shells are picked up in Liu Ling than in Jing Wong?

Draw a circle and report the result: there are two 4 in 8, and 8 is twice as much as 4.

Teacher's note: 8 is twice as much as 4. It can be expressed by a division formula: 8? 4=2

Let the students say: What does 8 mean? What do 4 and 2 mean respectively?

Teacher's Note: Time is not the name of the company. Students read a little knowledge about time together.

(2) Students independently solve "How many times more shells are picked up in Ming Ding than in Wang Ding?" AC formula, corrected result.

(3) How many times does Lin Jie pick up shells more than Li Fei? ,

Students solve independently and exchange ideas, and their understanding of 3 is 1 times that of 3.

Transfer learning: 4 is 0 times of 65438+4 and 5 is 0 times of 65438+5.

Student example: Tell me who is more than who 1 times.

Observation: What do these three questions have in common? Students exchange views.

Summary: Find out how many times one number is another like this, and you can also calculate it by division.

Design intention: In this link, let students further deepen their understanding of multiples through the calculation activities in the circle. On this basis, the division formula is introduced to make students realize that how many times one number is another can also be solved by the division formula. Transfer learning 1 times by solving problems. Then let the students read a little knowledge about "times" and understand that times represent the relationship between two quantities and cannot be used as the name of the unit.

V. Review, Summary and Improvement

Dialogue: What did you learn from this class?

Guide students to review and summarize the knowledge, methods and emotions they have learned. )

Talk: There are still many questions about time in our life. I hope you can find them with your little eyes of mathematics and calculate them with your little heads of mathematics. Okay？

Design intention: In this link, let students review and summarize from the aspects of knowledge, methods and emotions, sort out their thinking and cultivate their ability of induction and summary. Let students find and solve the multiples in life, communicate the relationship between mathematics and life, and experience the relationship between mathematics and life.