In the design process, not all teaching contents are suitable for micro-courses. Mathematics is a subject with spiraling knowledge, and many contents can be completed by students' mathematical ideas such as transfer analogy, guess verification and communication analysis. The process of completion is also the process of students' thinking development, so there is no need to do micro-courses. For example, in the last semester of the third grade, when students mastered division with remainder in written calculation, the example 4 on page 55 of the textbook "Solving problems by division with remainder" was no longer difficult for students, so there was no need to do micro-lessons. We summarize the contents suitable for micro-courses as follows.

1. Strong narrative knowledge points

Mainly refers to concepts, theorems and laws and other knowledge points. For example, in the last semester of Senior Two, in order to get the conclusion that 1 hour =60 minutes, the teacher asked the students to observe the clock face first, and guided them to observe that there were 12 large squares and 60 small squares on the clock face, and then calculated that it was 60 minutes for the minute hand to walk around. Finally, the students were asked to move the pointer by hand.

On the concept of angle in the last semester of Senior Two, the teacher can dynamically show the various parts of the angle by combining the graphics of an angle in the micro-class. At the same time, he tells that "starting from a point, the graphics composed of two straight lines are called an angle, and this point is called a vertex. These two straight lines are called edges, and an angle has a vertex and two sides". It is not just for students to make such knowledge into micro-courses.

2.

According to the assignment format, writing requirements and knowledge expansion

There will be more written homework in mathematics in the third grade than in the first and second grades. Teachers usually tell the whole class the requirements of homework writing and answering questions at the beginning of school, but these requirements are too many for most students to write down. At this time, the teacher can not only tell the students the homework requirements in the micro-class, but also show them the correct examples of homework pictures. With such a micro-lesson, children can watch it several times at home. In addition, teachers can classify according to different standards (for example, divide the format requirements into exercise books, exercise books and test papers, and make three micro-lessons respectively), so that students can choose to study in a targeted way.

If you explain a certain kind of difficult problem, such as calculating the perimeter of the figure 1, you can dynamically demonstrate the translation process in the micro-class, help students intuitively understand the transformation method, and finally turn the problem into a rectangle with a length of 10 cm and a width of 6 cm.

3.

Difficulties in explaining knowledge

For example, when teaching sophomores to know time, many students tend to read the wrong hours for the following types of time, such as 8: 55, 1 1: 50, so teachers can design a micro-lesson to help students understand how to read this type of time. For example, many students will also encounter difficulties in solving problems related to multiplication, which involve drawing line graphs. This paper expounds how to gradually transition from physical painting to line drawing. Every unit has knowledge difficulties, even in every class. Teachers should pay attention to collecting and understanding students' mastery.

4.

Method and process demonstration

This kind of micro-lesson is suitable for knowledge points with strong operability, such as crossing a point outside a straight line to make a vertical line, measuring angle, measuring length and so on. Taking angle measurement with protractor as an example, this paper explains the measurement method through PPT animation demonstration and presents it to students in text form. If the whole process of measuring the angle with a protractor is recorded with a camera tool for students to see, it will make students more aware of the use of the protractor in actual operation. It is not only more intuitive, but also much less than making PPT and customizing animation. However, it should be noted that the micro-lesson video should be accompanied by a text description of the operation steps.

How to design micro-courses

1. When making micro-lessons, teachers need to accurately grasp how many knowledge points the teaching content contains, and each knowledge point needs to be upgraded at several levels, which levels can be reflected in micro-lessons and which levels should be upgraded in classroom learning.

In the flip class of "Drawing a Vertical Line" by Mr. Hou Yongxian in our school, the teaching content includes three knowledge points, namely: crossing a point on a straight line to make a vertical line of a known straight line; A point outside the straight line is perpendicular to the known straight line; A point outside a straight line has the shortest distance to this straight line. For the teaching content, Mr. Hou first made a detailed analysis, so he made three short micro-lessons for students to learn independently before class: micro-lesson1-crossing a point on a straight line to make a known vertical line; Lesson 2-crossing a point outside the straight line as the perpendicular of the known straight line; Micro lesson 3- the distance between a point and a straight line. In order to highlight the correct drawing method, some wrong drawing examples are presented in the micro-lesson. For the knowledge point of "the shortest distance between a point and a straight line", a short story is introduced in the micro-lesson. It is proved by animation that the vertical line segment is the shortest among several line segments, and the length of the vertical line segment refers to the distance from this point to a straight line. It is necessary to analyze these three knowledge points and apply the properties of vertical line segments in class. The difference between vertical line and vertical line segment. Only by distinguishing clearly can students make no mistakes in solving practical problems by using the properties of vertical line segments.

2. As an important means of auxiliary teaching, the design of micro-courses should complement each other with self-study reports and classroom teaching, and be in-depth at different levels. Fig. 2 is a structural diagram of the implementation and achievement of micro-lessons, self-study reports and classroom teaching design goals in the section "Drawing Vertical Lines" by Mr. Hou.

Figure 2 shows that micro-class, self-study report and classroom teaching complement each other, and * * * together constitute a unified level of flipping the classroom.