The review of this unit includes the main contents learned in this book. Reviewing * * * is divided into eight parts: position and direction, divisor is the division of one digit, two digits are multiplied by two digits, statistics, the preliminary understanding of year, month, day, area and decimal, and solving problems. The review focuses on divisor divided by one digit, two digits multiplied by two digits, statistics, area and applying what you have learned to solve simple practical problems. Other contents are also important, and students should understand and master them effectively. Unit 9 "Mathematics Wide Angle" in this book is mainly to cultivate students' mathematical thinking methods. Students only need to know, so they don't review separately in the general review. Students can initially understand the thinking method of set and equivalent replacement through practice.

The arrangement of the general review highlights the following points.

1. Pay attention to the internal relationship between knowledge, facilitate sorting and comparison in review, and thus strengthen students' understanding and mastery of what they have learned. For example, in the topic 11on page12, we not only reviewed the identification of other seven directions according to a given direction (north, south, east or west), but also described the direction of an object with these direction words. At the same time, I will also look at the simple road map. In addition, it also lays a foundation for further learning to determine the position of objects according to direction and distance and describe simple road maps.

2. Pay attention to strengthen the connection with real life and strengthen the cultivation of estimation consciousness and ability. For example, in questions 2 and 4 on page112 ~13, the second question is designed to estimate and calculate the average monthly electricity consumption of three families, so that students can experience the application of division in life.

3. Strengthen the cultivation of statistical concepts. For example, the fifth question on page 1 13 not only reviews the simple analysis of the data, but also makes a simple judgment and prediction according to the analysis results; I also reviewed the meaning of average, and I will find the average of simple data. At the same time, it infiltrated environmental education.

4. Strengthen the cultivation of space concept. For example, questions 7 and 8 on page 1 14 not only review the basic knowledge about the area, but also review the area estimation of given rectangles and squares, so that we can choose appropriate area units to estimate and measure the area of the graph.

5. Strengthen the cultivation of problem-solving ability. In the general review, the application of number and calculation, space and graphics, statistics and other content itself is to solve the problem; In addition, some problem-solving contents are arranged separately, such as 1 1 and 12 questions 1 15, so that students can understand that some simple problems in life can be solved by multiplication and division.

Teaching suggestion

1. This part can be reviewed in 5 class hours. When reviewing, we should focus on reviewing the main contents of this unit. Teachers should know what problems each student has in their study, and inspire and guide students to solve them on the basis of independent thinking and cooperative communication. When reviewing other contents, teachers can master flexibly according to the actual situation, focusing on reviewing the contents that students have not yet mastered firmly, so that students can achieve the teaching objectives of this semester.

If there is flexible time, teachers can arrange time to systematically sort out and review the contents of the first issue (the first six textbooks) according to the fields of number and calculation, space and graphics, statistics and probability. , so as to fully complete the teaching objectives of the first phase.

2. When reviewing the orientation and direction, combined with the title 11on page 2 of the textbook, students can first say what is around Xiaoqing's home with eight orientation words; Then communicate with the whole class, and talk about how to identify the direction and describe the direction of the object in words, so as to understand the simple road map. Teachers can add several bus routes to the map to enrich the situational content; You can also redraw a simple map according to the local actual situation and ask the students to describe it.

3. When reviewing the division in which the divisor is a single digit, let the students do the second question on page 1 12 to understand what problems still exist in students' calculation, inspire and guide students to find their own mistakes and correct them through reflection; Also pay attention to make students skilled in calculation through certain exercises.

4. When reviewing the two-digit multiplication, review the oral calculation in combination with the third question on page 1 13, and review the estimation and written calculation in combination with the fourth question. The teacher corrects the problems in the calculation, and then through the related exercises in Exercise 25 or some targeted exercises, all students can achieve the teaching objectives stipulated in this semester.

5. When reviewing statistics, students are required to analyze the data in question 5 on page 1 13, and have a judgment on the development and change trend of sandstorm weather in this area in recent years; Let the students talk about their feelings. How to reduce dusty weather and let students receive environmental protection education?

6. When reviewing the year, month and day, we should pay attention to comprehensively reviewing the time units and related knowledge we have learned. We can systematically sort out the time units with tables, let students know the size of these units with examples, and cultivate their estimation ability.

7. When reviewing the area, combined with the seventh question on page 1 14, let the students use examples to establish the representation of area units and know the progress between two adjacent units. 1 14 page 8, let students estimate independently first, then cooperate with each other to measure, and then communicate with the whole class; Let the students with more accurate estimation talk about how they estimate, and let the students with less accurate estimation talk about where the errors appear, so as to improve students' estimation ability and measurement ability.

8. In reviewing the initial understanding of decimals, in addition to combining questions 9 and 1 15, some examples can be used to guide students to understand the basic meaning of decimals and the relationship between decimals and fractions with denominators of 10 and 100.

9. When reviewing problem solving, you can combine the questions 1 1 and 12 on page 15 to find out whether the students understand the quantitative relationship in the questions and can calculate them correctly. Enlighten and guide students with difficulties to meet the basic requirements. Pay attention to let students choose the correct answer according to the conditions and questions given in the topic, and do not require a student to master multiple methods.

10. Explanations of some exercises in Exercise 25 and teaching suggestions.

Question 3, let the students estimate first, and then calculate with a pen. Some students may have different answers from the written test, such as taking 58 as 60, 1 1 dang 10, and the estimated result is 600. The answer is that these people can't be sent away at once; The actual situation is 58× 1 1 = 638, and these people can be sent away at one time. The above estimation method is ok according to the general idea, but it gives the opposite answer. At this time, teachers should guide students to think about how to choose appropriate estimation strategies when facing practical problems, so as to solve the problems. The problem with the above estimation method is that 1 car can seat 58 people. If 1 1 is regarded as 10, it means that 58 people have been lost, which is quite different from 620 people. Therefore, 60× 1 1 = 660 is more suitable for estimation. Because 58 is regarded as a 60 1 car with two more people and a1car with 20 more people, the error is relatively small. Only in this way can we get the correct answer that "these people can be sent away at one time".

Question 5: By analyzing the data, let the students have a judgment on the changing trend of per capita grain consumption. Teachers should guide students to understand that with the development of social production, people eat more and more, so the per capita consumption of food is getting less and less.

Question 9, 13, teachers should attach importance to environmental education in combination with the topic.

The last thinking problem of Exercise 25 is to infiltrate the thinking method of equivalent substitution, and use this thinking method in the third period of learning binary linear equations. The solution to the problem is as follows.

According to the conditions in the question:

3 glasses of water+empty bottle = 440,

2 glasses of water +3 glasses of water+empty bottle = 600,

So 2 cups of water +440 = 600, 2 cups of water = 600-440, 1 cup of water = 80g.

Empty bottle = 200 grams.