The "multi-digit understanding" studied this semester is based on the understanding of numbers within 100 million in the second semester of Senior Two, and further study the understanding of numbers within 100 million and above 100 million. For the understanding of numbers, the focus is on several aspects of the concept of numbers, including the recognition, reading, writing and size comparison of numbers. Compared with the understanding of the number within 10 thousand, several levels of concepts began to appear in this textbook. Using the consistency of different levels of digital reading and writing methods, students can understand the general methods of digital reading and writing, highlight the regularity, and emphasize the use of transfer analogy to learn, which is based on decimal counting. Roundness is also the first time in this textbook, and it is also one of the key points of review.

2. Review of the Method of Multiplication and Division.

According to the requirements of the Standard, the range of written multiplication and division of integers is limited to three digits multiplied by (divided by) two digits. The content of this semester is the final stage of written multiplication and division of integers. This part of the review focuses on the calculation method of pen multiplication and division. In the calculation process, students can solve simple practical problems by using the relationship between factor and product and the changing law of quotient flexibly.

3. Review of Space and Graphics.

There are two parts about "space and figure" in this textbook: angle measurement, parallelogram and trapezoid. Among them, the measurement of angle is the basis, and the relationship between two straight lines on the same plane is only intersection and parallel, and verticality is a special case of intersection. To judge whether two straight lines are perpendicular, you must have the knowledge of angle measurement. The concept of parallelism is the basis of learning parallelogram and trapezoid. These geometric concepts are closely related, so it is difficult to separate one concept from others.

4. Review of Statistics.

The main content of "statistics" in this textbook is composite bar chart. The focus of review is to let students know the special function of this statistical chart. In the composite bar chart, we can see the differences of different types of data in each group of samples, the differences of data in different groups of samples, and the overall trend of data changes. In addition, it is also the focus of this part of the review to let students learn to analyze the data in the statistical chart and ask questions openly according to the information in the statistical chart.