Through general review, the knowledge learned in this semester is systematically and comprehensively reviewed and sorted out to help students build a reasonable knowledge system, so that students can better understand and master the concepts, calculation methods and related regular knowledge they have learned, further develop students' concepts such as number, space and statistics, enhance students' comprehensive ability to use knowledge, and fully realize the teaching objectives of this semester.

(2) Description of teaching materials

The review of this unit includes four parts: fraction multiplication and division, percentage, space and graphics, and statistics, covering the main contents of this book. Unit 7 Mathematics Wide Angle aims to cultivate students' logical reasoning ability and experience the generality of algebraic methods through interesting "chicken and rabbit in the same cage" problems. There is no specific requirement for this part, so there is no separate review content in this unit.

In the specific arrangement of content, this unit takes the standard knowledge field as the main line, not only follows the order of knowledge learned, but also concentrates on arranging related content, such as the content of fractional multiplication and division, space and graphics. On the one hand, it is to sort out and review the newly learned knowledge. On the other hand, it highlights the internal relationship between knowledge and facilitates students to form a knowledge network.

The following will briefly explain the contents of each part of the general review.

1. Fractional multiplication and division.

Fraction multiplication and division belongs to the basic knowledge and skills of fractions, and they are closely related, so the textbook arranges these two parts together. The textbook first emphasizes the relationship between fractional multiplication and division through a set of questions, that is, fractional division is the inverse operation of fractional multiplication. At the same time, the calculation method of fractional multiplication and division is reviewed. The related concepts of ratio, the concept and calculation of reciprocal, the nature of ratio, and the relationship between ratio and fraction and division are also the focus of review. Review the textbook by reviewing the second question and the third, fourth and fifth questions in exercise 27.

In addition, solving problems by fractional multiplication and division is also the key content of this part, which mainly includes the question of what is the score of a number (including slightly complicated) and the question of what is the score of a number (including slightly complicated). They are arranged in contrast in the textbook, which is convenient for students to understand the connections and differences between these kinds of problems, so as to better grasp the thinking of solving problems, that is, first make clear the unit "1", and then determine the method of solving problems according to whether the unit "1" is known or unknown. In order to let students master the analysis method better, they always review the fifth question and the seventh question of exercise 27, and also arrange the exercise that needs to judge the unit "1" twice.

2. percentage.

The review of percentage content focuses on the application of percentage, which is arranged after solving problems by fractional multiplication and division, so that students can see their consistency in structure and problem-solving ideas and strengthen the connection between knowledge. The concept of percentage has not been reviewed separately, but it is the basis of percentage application, so we should pay attention to review it. Always review the sixth question and seek the common ratio. By giving the calculation formula, we can not only review the meaning of percentage, the relationship between percentage and fraction and decimal, but also review the similar problems such as finding drying rate. The seventh topic is the slightly complicated percentage application. The questions 13, 14 and 15 in Exercise 27 are about percentages, among which 15 involves the review of national debt, tax payment and interest rate.

3. Space and graphics.

This part includes the review of position and circle.

In the first issue, students have used the first group and the first group to indicate the position of objects. This semester, they will further learn to use number pairs to represent the position of objects. In the textbook, the number pair is used to indicate the position of the object by reviewing the eighth question, and the corresponding exercise is arranged for the 1 question of exercise 27.

This semester's understanding of the circle includes the concepts of diameter, radius, π, axisymmetric figure, the circumference and area of the circle, and the drawing of the circle. The textbook focuses on reviewing the formulas for calculating the circumference and area of a circle and axisymmetric graphics. Review the ninth question in general, so as to deepen students' understanding and mastery of the calculation formula by allowing students to review the acquisition process of the calculation formula, so that students can flexibly use the calculation formula according to different conditions and problems when solving specific problems. 10 review the concept of axisymmetric graphics, use the concept to judge whether two graphics are axisymmetric graphics, and deepen students' understanding and arrangement of concepts. Review the knowledge of diameter, radius and their relationship in Exercise 27, Question 1 1.

4. statistics.

The main content of statistics this semester is to know the fan chart. By reviewing the question 1 1 in the textbook, students can further understand the characteristics of fan-shaped statistical charts, that is, they can clearly show the relationship between the number of each part and the total number, and solve some problems according to the given information, thus promoting students' ability to analyze information and solve problems.

(3) Teaching suggestions

This part of the content can be reviewed in 4 class hours, and the teacher can also master it flexibly according to the actual situation of the class.

Before reviewing, teachers should fully understand the students' mastery of this semester's knowledge, such as the degree of understanding of concepts, the degree of mastery of confusing concepts, the correct rate of calculation, and the general error-prone problems, and formulate appropriate and effective review plans according to specific conditions.

In review, from the perspective of knowledge, we need to pay attention to two points: First, we should pay attention to highlighting the core knowledge, key points and difficulties, so that students can establish the main knowledge context and improve the review efficiency. For example, to review the knowledge of fractional multiplication and division, we should understand the concept and calculation method of fractional multiplication and division, find out the similarities and differences of the calculation methods of fractional multiplication and division, improve the accuracy of students' calculation and master basic skills. Secondly, we should pay attention to let students master all parts of knowledge, further strengthen the connection between all parts of content, and help students establish a reasonable knowledge system. Connections include vertical and horizontal connections between knowledge. Vertical connection, such as location knowledge, should be based on the location knowledge of the first grade and the next semester, and appropriately compared with the existing knowledge; Horizontal connection, such as the connection between the application of percentage and the solution of fractional multiplication and division. From the perspective of students, we should pay attention to students at all levels when reviewing. For students with learning difficulties, we should help them find out the gap, guide them to find out the lack of knowledge, and carry out some basic exercises to meet the requirements of curriculum standards. For students with higher development level, we should meet their further needs, such as completing some comprehensive exercises or slightly more difficult exercises. In short, we should make corresponding plans and choose different review methods according to different contents and different students.

The following is a brief explanation of the problems that should be paid attention to when reviewing each part.

1. When reviewing the fractional multiplication and division method, you can ask each student to write a fractional multiplication formula first, and then write two corresponding fractional division formulas according to this fractional multiplication formula. Ask students to talk about the relationship of fractional multiplication and division through group communication, and recall and summarize the connection and difference of the calculation methods of fractional multiplication and division (for example, dividing a number that is not equal to 0 is equal to multiplying its reciprocal, and the following calculation methods are the same as fractional multiplication, etc.). Then, combined with the third question in Exercise 27, guide the students to review the related concepts of reciprocal, and let the students discuss with each other how to find the reciprocal of a number.

Review the concept of ratio, let the students start with the relationship between ratio, division and score, make their own lists and give examples. Then review the basic properties of ratio through exercise 27, question 4, and pay attention to the relationship with quotient invariance and fractional basic properties. When reviewing this part of the content, we should pay attention to two points: First, we should focus on reviewing concepts that are easy to be confused and clarify the connections and differences between concepts. Secondly, pay attention to the connection between knowledge and connect the knowledge of ratio, division and fraction.

The review of fractional multiplication and division can also be done by students. Then, by organizing students to exchange ideas on solving problems, the focus of review is on analyzing the quantitative relationship, so that students can better grasp the ideas on solving problems through comparison. For solving relatively simple problems (such as the fourth question in the general review), it is necessary to make clear who is who's what score, that is, what is regarded as the unit "1", and then judge whether the unit "1" is known or unknown, so as to decide the method of solving the problem. For slightly complicated problem solving (such as questions 3 and 5 in the general review), first determine the unit "1", then analyze and write out the basic relationship contained in the problem, and then determine the problem solving method according to whether the unit "1" is known or unknown. When reviewing, we should pay attention to let students further clarify the idea of solving the problem of fractional multiplication and division by comparative method (for example, we always review the two small questions in question 3); Special emphasis should also be placed on the important role of line segment diagram in analyzing quantitative relations; At the same time, pay attention to remind students to examine the questions comprehensively before doing them, and choose the calculation method flexibly according to different questions.

2. When reviewing percentages, we should pay attention to the comparison with relevant knowledge and strengthen the connection between knowledge. In specific teaching, students can recall and list what they have learned first. By exchanging the concept of review percentage and its relationship with scores, on this basis, the teacher presents simple application problems of percentage, such as 13 in the sixth question and exercise 27, and compares it with the problem that one number is a fraction of another number in the second volume of grade five, so that students can make it clear that their solutions and ideas are basically the same, but in the end they have to multiply it by 13. The slightly more complicated percentage application should also be compared with the fractional multiplication and division method to analyze the consistency of the two problem-solving ideas. The review of discount, tax payment and interest rate can be combined with 14 and 15 in Exercise 27.

3. When reviewing the position in space and graphics, students can actually play Go, and tell the position of each move in pairs, so that students can consolidate what they have learned in practical activities. You can also present a large Go board on the blackboard to show the Go board and chess pieces in the general review, so that students can use several pairs to indicate their positions. Then complete the 1 question in Exercise 27, and realize the position change according to the change of the number pair. Finally, students are required to make a general review of the methods of determining the position, that is, determining the position of objects by rows and columns, and determining the position of objects by pairs, and understand the relationship between the two methods. When reviewing circles and axisymmetric figures, let the students recall the knowledge of circles freely, and then finish the questions 1 1 and 12 in Exercise 27 after communication. Pay attention to two points when reviewing. First, make more use of objects and figures to guide students to recall the related concepts of circles and axisymmetric figures, as well as the formulas for calculating the perimeter and area of circles. Second, we should pay attention to how to review formulas, so as to prevent students from memorizing or confusing formulas.

4. When reviewing statistics, students can first be presented with the general review question 1 1, so that students can recall the fan-shaped statistical chart and its characteristics, and let students talk about what information can be obtained from the statistical chart, so as to further improve students' ability to obtain information from the statistical chart. Then students can ask their own questions, or they can present the problems in the textbook and let them solve them themselves. Finally, complete 16 and 17 in Exercise 27. The review of this part of the content can be combined with the review of the contents of broken line statistics and histogram statistics. Through comparison, students can understand the characteristics of departmental statistical charts more prominently and strengthen the connection between knowledge.

5. Explanations of some exercises in Exercise 27 and teaching suggestions.

Question 1 Let the students first express the position of the point in the graph, and then transform the fish pattern into the grid paper according to the given conditions, so that the students can experience the changes of the graph caused by the changes of the numbers in different positions in the number pair. Of course, you can also change the figure first, so that students can show the position of the new point after the change, and then compare it with the position of the original point, so that students can find the law.

Question 3: After the students write the countdown, let them talk about the meaning and calculation method of the countdown, and let them talk about why a single number can't be called the countdown.

Question 4: Before calculating, let students talk about what is the simplest integer ratio and think about how to turn each ratio into the simplest integer ratio to help students consolidate their knowledge.

Question 5: After students think and judge independently, they can also tell the reasons for right and wrong, thus deepening their understanding.

Question 7: The unit "1" needs to be judged twice. In the process of analyzing the quantitative relationship, students should first specifically say who they regard as the unit "1", and then who they regard as the unit "1", so that students can clearly understand the importance of analyzing the unit "1" in solving the problem of fractional multiplication and division. Question 8 can also be handled similarly.

Question 1 1, you can talk about why after the students finish.

14 gives a lot of different kinds of information through the situation diagram, allowing students to ask questions and solve problems by themselves according to the information provided, which is a very open topic. Teachers can make full use of this topic and consolidate students' knowledge about percentage, discount and fractional multiplication and division.

15 involves national debt, interest rate and tax knowledge at the same time. Teachers can introduce the knowledge about national debt to students from this question and consolidate other related knowledge.

Questions 16 and 17, in teaching, first, let students know the characteristics of fan-shaped statistical charts, and let students fully read information from statistical charts, and then ask questions and solve problems by themselves. You can also directly present the problems in the textbook for students to solve. Question 17 also allows students to make some practical investigations based on the collected information and put forward effective measures to improve air quality.