Knowledge and skills

With the help of line graph, students can deepen their understanding of the concept of multiple, solve the practical problem of "how many times is a number" by multiplication, correctly distinguish two kinds of multiple problems, cultivate students' ability to solve problems by applying concepts, and cultivate geometric intuition and model thinking in the process of solving problems.

(2) Process and method

Cultivate students' abilities of observation, analysis, cooperation and communication, language expression and rigorous examination of questions, attach importance to the role of geometric intuition, help students understand mathematics through various intuitive forms, provide students with opportunities to participate in geometric intuitive activities, and accumulate experience in learning mathematics with pictures.

(3) Emotional attitudes and values

Experience the joy of success in the process of independent exploration, cooperation and communication, and problem solving.

Second, the diagnosis and analysis of teaching problems

The learning content of "how many times is a number" is still an abstract knowledge for the understanding ability of junior three students. Although children have a certain foundation in the concept of multiples and know the relationship between "1 weight" (standard quantity) and "comparative quantity", these mathematical languages are far from easy to understand. There are many practical problems in teaching that need to be designed. Only by abstracting the "objects" of research into "figures" and then transforming the "relationship between objects" into "relationship between figures" can we gradually shift from the consolidation of old knowledge to the study of new knowledge, so that the research problem can be considered as the problem of "quantity or position relationship of figures", and then we can think and analyze it, which is convenient for students to establish mathematical models to solve such problems in comparison and abstraction. By letting students learn how to draw a line diagram to express the quantitative relationship and understand the meaning of the problem, students can clearly solve the problem of "how many times is a number" by multiplication. In the teaching of "How many times is a number", in order to reduce the difficulty of students' understanding of knowledge, the fewer the number, the better, and allow students to use learning tools as much as possible to deepen their understanding of knowledge through intuitive images. Combining the knowledge of previous classmates, we can find the correct solution.

Third, teaching focuses on difficulties.

Teaching emphasis: The teaching emphasis of this lesson is to explore the calculation method of how many times a number is and the relationship between times.

Teaching difficulties: using the learned method of "seeking a few" to solve new problems and realize knowledge transfer.

Fourth, teaching preparation.