What is the understanding of "how many times is a number"?

First, the design ideas

The content of this lesson is mainly to cultivate students' interest in learning mathematics, stimulate students' potential and solve the practical problem of "how many times is a number". Let them realize that there is a lot of mathematical information in real life. When facing practical problems, students can actively try to use what they have learned and various forms to find solutions to problems from the perspective of mathematics. In the face of new mathematics knowledge, through self-exploration and hands-on operation, we actively seek solutions to problems, so that students can feel that mathematics comes from life and there is mathematics everywhere in life.

Second, teaching material analysis

This teaching content is on page 77 of the textbook. It is based on students' initial understanding of several times, with the thinking structure of "how many times is a number" extended by "share" and "how many times is a number", and designs a picture of two primary school students walking in the park. In this scene, two mathematical messages are displayed through the children's dialogue. Six poplars have been planted, and the number of willows is three times that of poplars. ) According to these two mathematical information, let the students ask a mathematical question. The focus of teaching is to guide students to learn to analyze the relationship between two numbers from practical problems, which is also the difficulty of teaching. The key is to understand that a number has several identical numbers, which are several times of another number, and then know that several times of a number are calculated by multiplying several numbers. In specific teaching, students should operate learning tools independently, break through difficulties, understand the relationship between conditions and problems, and then organize students to communicate, inspire each other in interaction and communication, and deepen their understanding of knowledge. Finally, teachers can summarize and tell intuitively and vividly with the help of multimedia demonstration line drawing.

Thirdly, the analysis of learning situation.

According to the age characteristics, psychological characteristics, cognitive rules and thinking development of junior students, I designed a link to break through obstacles in teaching, including (I can talk, I am a little teacher, I can calculate, I am a smart bridge) to stimulate students' interest in learning and make them feel good about mathematics. Make the connection between old and new knowledge closer, and make students' learning state naturally change from the consolidation of old knowledge to the learning of new knowledge. Stimulate students' interest in exploring situational mathematics problems and let them find and solve problems on their own initiative. Students can operate learning tools independently, then organize students to communicate, inspire each other in interaction and communication, and deepen their understanding of knowledge.

Fourth, teaching objectives.

1, knowledge and skills: on the basis of students' understanding of the concept of "times", guide students to learn to use the knowledge of times to solve the practical problem of "how many times is a number".

2. Mathematical thinking: experience and understand mathematics in real situations, cultivate students' ability to think and explore problems actively, and cultivate students' ability of observation and analysis and language expression.

3, problem solving: in the problem scenario can accurately capture mathematical information, take the initiative to solve the problem.

4. Emotion and attitude: Let students feel that mathematics comes from life, and there is mathematics everywhere in life. At the same time, cultivate their love for mathematics and produce feelings of loving mathematics.

Fifth, the teaching focus, teaching difficulties

Teaching focus

1, learn how to solve an application problem, and be able to answer it correctly.

2. Learn to analyze the relationship between mathematical information and the questions raised, and learn to look at line graphs.

Teaching difficulties

Analyze the meaning of key sentences, understand the multiple relationship between two quantities in the topic, and get the solution.

Teaching focus

With the help of line drawing or learning tools, understand that a number has several other numbers in common, and this number is several times that of another number. Then, according to the method of finding several times, we can know how many times a number is by multiplication.

Six, teaching strategies and means

This teaching design adopts inquiry teaching mode, which makes students become the main body of learning, develops students' practical ability through hands-on operation, cultivates students' learning habits of hands-on, brain-use and verbal communication, and pays attention to the cultivation of students' thinking ability.

Seven. Preparation of teaching AIDS

Some pictures of triangles and disks, poplars and willows.

Eight, the teaching process

First, review the old knowledge.

Teacher: Students, we just met a new friend yesterday. who is it? (Time)

Do you like it? Read it out loud together.

Health: Read Time.

Teacher: Last class, we learned the basic knowledge of the times. What knowledge have you learned?

Student: Who is the copy, who has so many copies, how many copies, and who is several times.

2. Teacher: What you said is really good! Let's enter the first level of happy mathematics "I can talk"

Light light blue has just listened to the students' speeches and put forward a question to everyone. Please say it with your knowledge.

(1) Teacher: Show ppt.

The first line pendulum:

Second pendulum: △△△△△△△△△

The number of delta is _ _ _ times.

Follow-up: Why is the number of △ three times that of △?

(2) Teacher: What you said is great! Xiao Ming also brings you a question. Who will say?

Teacher: Show ppt.

The first line:

The second line:

The number of bars in the second row is _ _ _ times that in the first row, which is _ _ _ _ _.

Health: Say.

Teacher: What do you think?

Today we will continue to learn multiples.

Teacher: Show ppt.

Blackboard: What is the multiple of a number?

Second, the introduction of new grants:

1, Teacher: Show the ppt situation diagram.

On Sunday, two students were walking in the park. The scenery in the park is really beautiful! What did they say as they walked?

Teacher: Please look at the picture carefully. What math information can you tell teachers and students from the pictures?

Health: Six poplars have been planted, and the number of willows is three times that of poplars.

Q: According to these two pieces of mathematical information, what mathematical questions can you ask?

Health: How many willows have you planted?

Teacher: Show ppt.

2. Teacher: Please describe the math information and problems completely. Name theory

Teacher: The teacher has arranged the information in this picture into words. Come and read it.

Let me see: six poplars are planted, and the number of willows is three times that of poplars. How many willows have been planted?

3. How many willows do you need to plant? Which sentence do you think is the most important?

Health: There are three times as many willows as poplars.

Display: The number of willow trees painted red is three times that of poplar trees.

Teacher: Why?

Name: ① The ratio of willow to poplar ② Six poplars are 1.

(3) There are three willows, that is, three sixes, so we say that the number of willows is three times that of poplars.

4. Teacher: How many willows are required to be planted? Can you solve this math problem in the way you like?

Student: Let's discuss in groups of four.

Student: discussant: patrol

This class takes 15-20 minutes.

5. Teacher: Which group will enter the second level of Happy Mathematics "I am a little teacher" first?

Teacher: Let the students speak in groups.

(1) Group 1: Our group solved this math problem by putting pictures.

Here's what we think,

Health: Put pictures on the blackboard to compare the reasons.

① The ratio of willow to poplar ② Six poplars are 1.

(3) There are three willows, that is, three sixes, so we say that the number of willows is three times that of poplars. In this way, our group will know the kind of 18 willow.

Teacher: You made it very clear. You deserve to be a little teacher. Please come back.

Q: Do you agree with this method of solving problems? Which group's method is different from theirs?

Teacher: Let the students explain before the physical projection.

(2) The second group: Our group solved this math problem by drawing line segments.

The following are our thoughts: ① The ratio of willow to poplar is 1, and there are 6 poplars.

(3) There are three willows, that is, three sixes, so we say that the number of willows is three times that of poplars. In this way, our group will know the kind of 18 willow.

Teacher: What about this little teacher? We applauded her.

Q: Which group's method is different from theirs?

Teacher: Let the students explain before the physical projection.

(3) The second group: Our group solved this math problem by column calculation.

The following are our thoughts: ① The ratio of willow to poplar is 1, and there are 6 poplars.

(3) There are three willows, that is, three sixes, so we say that the number of willows is three times that of poplars. In this way, our group will know the kind of 18 willow.

Q: Which group has the same method as theirs? You are smart, too!

Teacher: Who will write the formula on the blackboard?

The name written on the blackboard: 6 X 3 = 18 (tree)

18 willow trees were planted.

6. Teacher's summary: Just now, the students solved this math problem in different ways. Some are diagrams, some are drawing lines, and some are calculation formulas. These methods are based on

The teacher refers to the blackboard: ① The ratio of willow to poplar ② Six poplars are 1.

(3) There are three willows, that is, three sixes, so we say that the number of willows is three times that of poplars.

Then you will know how many willows have been planted. Just a few. How much is it?

Teacher: Actually, in life, we have such math problems around us.

Enter the third level of happy mathematics "I can calculate"

1, Teacher: Show ppt consolidation exercises.

These questions are all math around my classmates.

(1) Borrowing books from the library

(2) Oral calculation

(3) Compared with the age of teachers

(4) Skipping rope

(5) Do sit-ups

Methods: Find the students in the photos to read the questions and calculate the answers continuously.

Fourth, the teacher summary:

1. Q: What method did we use to calculate these problems just now?

Student: Multiplication.

Teacher: blackboard multiplication

2. Teacher: Show ppt, find out how many times a number is, and calculate by (multiplication).

Health: Read it.

Five, enter the fourth level of happy mathematics "intelligent bridge"

1, Teacher: Show ppt line drawing.

Student: Read the questions and understand the meaning.

Clear: The known condition of this problem is that there are seven yellow flowers, and the safflower is five times that of yellow flowers. The question is how many red flowers are there?

Health: The number of red flowers is five times that of yellow flowers, that is, there are five and seven red flowers.

2. Teacher: Show ppt.

Students go boating in the park in autumn. There are four times as many people in the big boat as in the small boat. It is a hidden condition that two people are sitting in a boat. How many people can sit in a big ship?

Health: Look for the second known situation through observation, and then solve the problem.

Sixth, enter the fifth level of happy mathematics "talking about experience"

Teacher: What have you gained in this math class?

Health: express your opinions.

Division; Students have gained a lot!

Seven. distribute

1, complete questions 2 and 3 on page 78.

2. a little

There is 12, which makes one part several times that of the other. How many ways do you divide it?

Teacher: Class is over.

Blackboard design:

What is the multiple of a number?