Li Du Ansai county 2 nd primary school

Teaching content:

The second volume of the second grade of primary school mathematics published by People's Education Press (Example 2 and Example 3 on page 54 of the textbook)

Design concept:

"Times" is an abstract concept in primary school mathematics, and it is also a very important concept. It is the basis for further learning about multiples, and it is also the basis for learning knowledge such as scores and proportions. The concept of time is produced by comparing two numbers. One number is used as a unit, and the other number contains several such units, which is several times that of the former. Last semester, the students learned some knowledge about time and established a preliminary understanding of time. However, last semester, according to the number of times, what was it? What we need to complete now is the thinking process of figuring out how many times one number is another according to the knowledge of multiple relation and division. In order to prevent students from making cognitive mistakes, students should be allowed to operate repeatedly, pay attention to exposing their original state of learning, and teachers should help correct them, so that students can fully accumulate perceptual materials and experience the whole process of concept formation in a down-to-earth manner. At the same time, pay attention to the guidance of learning methods and cultivate students' awareness of application, cooperation and innovation.

Teaching material analysis:

The textbook begins to teach the practical problems of the multiple relationship between two numbers from here. The textbook first teaches several times as many application problems as the other one. Because teaching the application problem about the multiple relationship between two numbers, we should first establish the concept of "multiple" for students, contact an application problem in which one number contains several other numbers, and one number is several times that of another number, and also contact an application problem in which one number contains several other numbers. This arrangement of teaching will be smoother. The quantitative relationship of this kind of application problems is abstract, which is a bit difficult for students to understand. Teaching materials should pay attention to strengthening practical operation. First of all, students should establish the concept of "multiple" by swinging a stick, and connect several numbers with others in a number they have learned before. Then let the students set up sticks. Further let the students understand the meaning that one number is several times that of another number. On this basis, teach to find an application problem whose number is several times that of another. Make it clear that 35 is several times as many as 7. In fact, how many 7s are there in 35? Therefore, finding how many times a number is another number is different from finding how many other numbers there are in a number, but the terminology is different and the quantitative relationship is the same. In this way, the internal relationship between old and new knowledge can be communicated, and students can better grasp the quantitative relationship and problem-solving methods of this application problem.

Analysis of learning situation:

In this lesson, we should respect the differences of students' thinking level, guide students to gradually transition from intuitive thinking to abstract thinking through students' cooperation and exchange, learn to analyze the quantitative relationship by using the meaning of division learned, and initially understand how to solve practical problems through transformation.

Teaching objectives:

1, knowledge and skills: through practical activities, let students understand the meaning of "one number is several times that of another number" and understand the relationship between numbers.

2. Process and method: Make students experience the process of transforming the practical problem of "how many times is one number" into the mathematical problem of "how many other numbers are included in one number", and initially learn to solve simple practical problems by transformation.

3. Emotion, attitude and values: cultivate students' ability to practice, observe, analyze and solve problems.

Teaching emphasis: analyze the quantitative relationship and solve the application problems correctly.

Teaching difficulties: analyze the quantitative relationship and express the problem-solving ideas more concisely in your own language.

Teaching strategies and means:

1, review old knowledge. Arouse students' memory of knowledge about "time". Consolidate and deepen the understanding of the concept of "time". (The purpose is to make a cognitive preparation for solving the practical problem of "how many times one number is another". )

2, hands-on operation, preliminary exploration of new knowledge. Through effective mathematical activities, students can understand the meaning of "one number is several times that of another" in complete operational activities and simple language expressions. The purpose is to prepare for the practical problem of "how many times is one number another". By previewing the "theme map", let students ask the question "who is several times as many as who" and realize that there are multiple relationships between many quantities in life. The purpose is to prepare for the discussion and exchange of "in-class communication class" )

3. Consolidate the practice methods. Designing layered exercises with rich questions and various forms in applied knowledge can help students to consolidate their understanding of the meaning of multiples and the basic thinking method of "how many times is one number another". At the same time, stimulating students' enthusiasm for applying knowledge can also improve their ability to solve practical problems.

4. Summarize. Through the final summary of the teaching content, the process of topic selection is revealed, and the students' summary ability is improved.

Teaching preparation:

Teacher Preparation: Multimedia Courseware

Student preparation: 20.

Teaching hours: 1 hour.

Teaching process:

First, review old knowledge and introduce new lessons.

Computer display: 12 contains () 4.

There are () 3s in 15.

Q: How to calculate?

Second, hands-on operation to explore new knowledge.

(a) swing rod

1. Discharge two sticks at the first place (computer display)

Teacher: There are three sticks and two sticks in the second row. Can you let them go? (Will) Try it quickly.

Question: How many sticks did you put in the second line? (6) How do you know?

Student report

The computer shows 32/6. The teacher stressed that it can also be said that "the number of sticks in the second row is three times that in the first row" and asked the students to read together.

Teacher: Let's put two more sticks in the second row. How many sticks are there? What did you say?

Students report, and the teacher's computer shows: the teacher put it.

Question: Is the teacher the same as you?

Fill in the blanks: computer performance

8 includes () 2, and the number of rods in the second row is () times that in the first row.

The teacher stressed: it can also be said that 8 is several times that of 2.

3. Teacher: If the number of sticks in the second row is six times that in the first row, how should they be arranged? A * * * put a few?

Let the students swing.

report

The teacher asked: How many 2s are there in 12? What else can I say? (Instructor will prompt if necessary)

4. practice.

The computer shows that there are () sixes in (1) 12.

12 is () times that of 6.

(2) There are () 7s in 42.

42 is () times that of 7.

(2) Computer display situation map

1, Teacher: What do you know from the pictures?

Health report

Teacher: Can you put forward a math problem according to the conditions shown in the picture? Can you answer that?

At this time, the teacher can guide the students to ask a question of multiple relationship, and at the same time write on the blackboard: How many times are frogs more than cats?

Teacher: This question is what we are going to learn today. Derived problem: Find a number that is several times that of another (division) application problem.

4. Teacher: Can you answer? Students try to make formulas and reports, and the teacher writes formulas on the blackboard.

Question: Why do you use division? Prompt students to write answers.

The teacher stressed that they are multiples, so "multiples" cannot be used as units.

5. Teacher's summary: As mentioned above, finding the application problem that one number is several times that of another number is actually a practical problem of how many other numbers a number contains, so it must be calculated by division. At the same time, write on the blackboard: (division)

Third, consolidate the practice.

Computer display:

1, desk lamp 49 yuan desk calendar 7 yuan

How much is the price of a desk lamp?

After the students finish independently, the whole class will check.

2. Judges

Step 3 choose

4. Expansion problem

(1) Picture Frog 4 Monkey 8 Bird 2.

Ask the students to choose two animals they like and talk about their multiples.

Ask personal questions at the same table

(2) Pictures

Xiaoming said: I am 8 years old this year.

Xiao Liang said: I am 4 years old.

The army said: I am twice as old as Xiao Ming.

How old is Dajun?

Students are required to complete it independently.

Question: What do you think? How is it calculated?

Health report

Fourth, class summary.

What did we learn in this class? What have you learned?

blackboard-writing design

Find a division application problem in which one number is several times that of another number.

p； How many times are there frogs than cats?

35÷7=5

A: There are five times as many frogs as cats.

Task:

Teaching reflection:

The teaching difficulty of this course is the application of analytical reasoning, which transforms the quantitative relationship of "how many times one number is another number" into "the division meaning of other numbers contained in one number". Teaching design I strive to embody the process of "experience-understanding-solution-application" in mathematics learning.

1. Learn new knowledge from children's life experiences. This lesson, mainly through children's life experience, allows students to extract "how many times is one number another", which is actually "how many other numbers are there in a number". Through practical operation, observation and thinking, make students clear that if one number is several times that of another, one number should be divided by another. In teaching, I let students work together at the same table and build a plane map, which breaks through this knowledge point and makes students study easily and happily.

2. Pay attention to the development of students and cultivate their thinking consciousness. The main task of mathematics is to cultivate students' thinking ability. In this class, I use the visual image of multimedia to guide students to observe more, use the existing mathematical knowledge to solve practical problems, and let students feel the charm of mathematics in actual situations. According to the abundant information provided by pictures, we can choose some useful data, ask relevant questions and answer them with what we have learned. At the same time, according to the specific meaning of the question, guide students to carefully examine the question, ask questions and answer as required.

3. Pay attention to the cultivation of junior students' habits. Junior students are often inattentive and talkative in class. In class, I often ask students to pay attention to sitting posture and writing posture. Repeatedly remind students to pay attention to the lecture, not only to the teacher, but also to the students who answer questions. Therefore, I ask students to repeat the main points and questions in other people's speeches from time to time. For example, students often lose the word "divide" when reading division, which not only attracts the attention of students who answer wrong questions, but also attracts the attention of the whole class.

4. Pay attention to the cultivation of cooperative consciousness. There is often a lack of timeliness in the cooperation of junior students. Therefore, before cooperation, I pay attention to the requirements of cooperative learning and give individual guidance in time so that students can learn cooperative learning.

5. There is not enough guidance for individual students with learning difficulties in class. These students are not active in thinking and their enthusiasm is not fully mobilized. Too much colored chalk is used in writing on the blackboard, which makes it difficult for the students behind to read clearly. Continue to work hard in the future and constantly improve your teaching quality.