The understanding of trapezoid is the content of the fourth grade of primary school mathematics by People's Education Press, which is taught on the basis that students have mastered the characteristics of parallelogram. For the first time, systematically understanding the trapezoid according to the progress of the textbook requires students not only to make an intuitive judgment according to the characteristic that only one group of opposite sides are parallel, but also to compare and communicate with the parallelogram, rectangle and square they have learned before.

In this class, teacher Wen takes teachers as the leading factor, students as the main body, comparison as the main line, teacher-student interaction and independent inquiry as the main methods, supplemented by multimedia teaching, which makes mathematics close to life, reality and original experience, and enables students to actively learn mathematics, explore mathematics and learn mathematics happily, which fully embodies the classroom teaching structure mode of learning with teaching and achieves the predetermined teaching objectives.

Mainly manifested in:

First, fully demonstrate the occurrence, development and connection of knowledge, and pay attention to the process of knowledge formation.

With regard to the study of trapezoidal features, Mr. Wen tried to let students experience the formation process of knowledge. In the process of establishing trapezoidal representation, let students compare the characteristics of trapezoid and parallelogram continuously, deepen the difference between the two figures, and pave the way for students to communicate the relationship between quadrangles, choose exercises, integrate knowledge points and make full use of each exercise.

There are many knowledge points in this lesson, including the characteristics of trapezoid, the names of various parts, the particularity of right-angled trapezoid and isosceles trapezoid, and the height of drawing trapezoid. Therefore, it is particularly important to choose exercises, integrate knowledge and leave enough space for students to think and explore.

Teacher Wen's three exercises of judging questions, changing questions and guessing questions not only enable students to master the important and difficult points, but also develop their thinking.

Third, carefully design every question in the classroom.

After asking the students to teach themselves the upper bottom, the lower bottom, the waist and the height of 66 pages of the book, I didn't simply ask the students to tell the answer, but asked a student to point up and say: The upper bottom is ... The lower bottom is .................................................................................................'s report on the second right-angled trapezoid, and I asked, "Why is its height waist?"

Make students know more clearly on the basis of existing knowledge: if a waist of the trapezoid is perpendicular to the bottom of the trapezoid, then this waist is the height of the trapezoid. At the same time, students also know that what is not above is called the bottom, and what is below is called the bottom.

In a word, Mr. Wen can carry out the basic teaching concept that runs through the new curriculum standard of primary school mathematics, carefully design students' operation activities, and fully benefit from multimedia teaching methods. Teachers teach with a developmental perspective, pay attention to the process of knowledge formation, and pay attention to students' lifelong development and future ability. I think it would be better if students could practice a little more.