Solving problems plays an important role in mathematics teaching. It can not only cultivate students' consciousness and innovative consciousness, but also consolidate relevant knowledge and develop students' thinking. The teaching content of this lesson is to solve the practical problem of "how many times is a number" on the basis that students have known multiplication and mastered its meaning. Lay a foundation for solving more complicated problems in the future.

The content of this course is on page 77 of the textbook, and a picture of common scenes in students' daily life is designed. In this scene, the children are cleaning the classroom, among them, seven people are sweeping the floor, and the number of people cleaning the table is twice that of sweeping the floor. Give the math information through the dialogue and let the students ask questions. There is also a schematic and intuitive line diagram below to guide students to understand that twice seven is two sevens, so there are 14 people cleaning the table.

Before that, although students had the foundation of learning the multiplication formula of 7, they had a preliminary understanding of the concept of "several times of a number" and had formed the consciousness of actively exploring mathematical knowledge in real situations in their previous studies. However, it is difficult for students to separate the relationship between two numbers from practical problems. Therefore, the key is to understand that a number has several identical numbers, which are several times of another number, and then according to the method of finding several numbers, it is known that several times of a number are calculated by multiplication.

Therefore, I adopt inquiry teaching mode, pay attention to problem solving, pay attention to students' independent activities and cultivate students' thinking ability. In specific teaching, let students 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, with the help of multimedia or blackboard writing, it is summarized intuitively and vividly with line drawing.

Teaching design

Teaching objectives:

1. Let students go through the process of exploring the practical problem of "how many times is a number", master "how many times is a number" and use multiplication.

2. Through analogical reasoning and knowledge transfer, let students know that the quantitative relationship of the practical question "How many times is a number" is: the number of people sweeping the floor ×2 times = the number of people cleaning tables and chairs. Guide students to learn to analyze the relationship between two numbers from practical problems. In the problem scenario, we can accurately capture the mathematical information and actively solve the problem.

3. Cultivate the consciousness of independent exploration and cooperative communication, feel the wide application of mathematics in daily life, and enhance the positive emotion of learning mathematics. Stimulate students' feelings of loving nature.

Teaching emphases and difficulties:

Teaching emphasis: learn to analyze the relationship between mathematical information and the questions raised, and learn to read line graphs.

Teaching difficulty: understanding the multiple relationship between two quantities in the topic.

Pre-class preparation: self-made courseware and learning tools

Teaching process:

First, create an environment to stimulate interest

1, say it.

Teacher: We have learned the multiplication formula of 1-7. I heard that our class is very skilled in reciting formulas. Is that so? Teacher Lin came to check.

Show me the problem of oral calculation and the formula.

2. Fill it in.

Teacher: We learned twice as much knowledge last class. Cong Cong the elf wants everyone to fill it out.

Display: 2 blue flowers, 6 red flowers, the number of red flowers is () times that of blue flowers.

Teacher: Why three times? How much is three twos? It can be said that it is three times as much as two.

3, put a pendulum.

There are four blue flowers, and the number of red flowers is twice that of blue flowers.

Teacher: How should the number of red flowers be arranged? (Student operation) Teacher Lin has just made a tour and found that everyone poses like this. Why are you posing like this? (Two times four equals two. How much is four? )

Teacher: We know the "times" and understand the meaning of the times. In this lesson today, we will use the knowledge of the times to solve some practical problems in life. (blackboard writing topic: solving problems)

Second, independent inquiry.

(A) lead to questions and stimulate interest

1, Teacher Introduction: Today, Teacher Lin came to a primary school and found that the campus and teachers were clean. It seems that our little classmates are a group of good children who love labor and pay attention to hygiene. You see, the students in Class Two (1) are the same as others! (Show the situational diagram of Example 4 of the courseware)

2, the courseware shows dubbing: there are 7 people sweeping the floor, and the number of people cleaning tables and chairs is twice that of sweeping the floor.

Teacher: What are they doing? (Sweep the floor, clean the tables and chairs) (Post pictures)

(2) Capture information and analyze it.

1, looking for information.

Teacher: From these two pieces of mathematical information, whose number do we know?

(There are seven people sweeping the floor) (Put up pictures of seven little people)

Teacher: Did the number of people cleaning tables and chairs tell us directly? Are we all willing to help out? Everyone is not only a group of good children who love labor and care about health, but also a group of good children who help others! )

Teacher: How are you going to solve it? Is there any other way besides calculation? Write on the blackboard while telling the teacher (by posing, drawing and calculating). (blackboard writing: posing, drawing and calculating)

2. Put school tools.

(1) How many people ask students to clean desks and chairs with their school tools? Let's see who can swing fast and well! At the same time, I will go on stage to operate. (Move the picture down a bit)

After you put it away, tell your deskmate why you put it this way.

(2) The teacher asked the students who took the stage to operate: How did you put it? (Put two sevens) Why do you put it like this? (Two times seven equals two. How much is seven? )

(C) in-depth exploration, grasp the reasoning

1, Teacher: Don't pose. Teacher Lin has a convenient and clear expression. Do you want to know? (writing on the blackboard: painting) What are you drawing? Introduce a "new friend"-line diagram to students. (blackboard writing: line drawing)

2, the teacher hands-on demonstration line drawing. (Showing line segment ①) If this line segment is used to represent the number of people sweeping the floor. Think about it, class. How to draw the number of people cleaning tables and chairs? (discuss at the same table)

3. A little feedback. Teacher: What do you think should be done? (The painting is as long as two) Why do you want to draw it like this? (Two times seven equals two. How much is seven? )

Teacher's drawing: (showing line segment ②)

What does this paragraph mean? Refers to one of the paragraphs (7 people, moving pictures of 7 little people). What about this paragraph? What do you mean by such a long line? (Number of people cleaning tables and chairs)

4. The courseware demonstrates the line chart and reproduces the relationship between the number of people sweeping the floor and the number of people cleaning tables and chairs. The number of people cleaning tables and chairs should be as long as two sweeping the floor. )

(4) List solutions

1, teacher animated braces. Q: What are the problems that need to be solved? Show me the question: How many people are cleaning the desks and chairs? In order to solve this problem, we used the methods of posing and drawing. Can you calculate?

(7 digits removed)

2. Column calculation.

Students finish on the draft book and report on the blackboard: 7 2 =14 (person) or 2 7 =14 (person).

Teacher: Point to the "7" in the formula and say: What part does 7 stand for in the line graph? (Seven people sweeping the floor) What about it? What about14? (Number of people cleaning tables and chairs) Why do you use multiplication? (Finding seven twice means finding two sevens, so it is calculated by multiplication) (point 2-3 people say)

Teacher's summary: Find twice of 7, that is, find several times of a number, and calculate by multiplication.

3. Answer orally.

(d) Practice consolidation: do it.

Teacher: In the amusement park, the rabbits had a good time! Performance: Do it.

Teacher: What mathematical information do you know from the picture? How do you intend to solve the problems raised? Students try to do it before communicating. )

Key point: Why use multiplication? Guide the students to say the number of times to find a number and use multiplication. Ask several students to demonstrate, and then talk to each other at the same table. (Find 5 times of 3, that is, how many times of a number, and calculate by multiplication)

(5) Teacher's summary: These two questions are about how to calculate how many times a number is (blackboard topic: How many times is a number, students read it together). (Multiplication) During this period, what methods did we use? (How to pose, draw and calculate) In drawing, we also met a new friend-line graph, which is a good helper for our study. A line chart can help us clearly see how many times a number is. Find how many times a number is' that is, how many times this number is, and calculate by multiplication. Therefore, through today's study, as long as the problem of' how many times is a number' is solved in the future, it can be calculated directly by multiplication.

Third, practice internalization.

Show the scene map. You see, there are many interesting places here. Do you want to go? Where are you going?

1、

Science Park: Question 6 (see the solution of drawing lines)

2. Question of Gong Yuan 7

(One condition is missing)

Teacher: Why don't you do it? What didn't you tell me? (The number of blue balloons) Please add a message to it! The teacher will add another one! Let me see (there are six blue balloons). Can you solve the problems in The Red Baron now?

3. Problems with zoos 8

(Give one more condition) Multiple choice questions

Fourth, summarize and expand.

1. What have you learned through today's study? What do you think of your performance in this class? Who performed well?

2, expand the practice to see the line drawing application questions.