1, determine the central theme of this unit, that is, multiplication and division of decimals. As the center of mind map, this theme will be the cornerstone of the whole mind map, and on this basis, it will be classified.

2. According to the content of the textbook, divide the main knowledge points of this unit. For example, decimal multiplication, decimal division, decimal mixed operation and so on can be used as the main knowledge points. These knowledge points are the second layer of mind map, which provides a framework for the following details.

3. Fill in the specific details and contents under the major knowledge points. For example, under the knowledge point of decimal multiplication, it can include details such as calculation method, example analysis and matters needing attention; Under the knowledge of fractional division, it can include details such as calculation method, example analysis, and error-prone points. These details will serve as the third layer of mind mapping, enriching and perfecting the whole mind mapping.

4. In the process of making mind maps, graphics, colors, symbols and other elements can be used to enhance the visual effect and make mind maps more vivid and interesting. For example, lines of different colors can be used to represent different levels of knowledge; Mark important or difficult points with vivid graphics or symbols; Use different fonts or sizes to distinguish different levels of knowledge.

The function of mind map in the fourth unit of mathematics;

1. Mind mapping helps students understand knowledge systematically. By connecting various concepts and knowledge points in the form of trees or networks, mind map reveals the internal relations between knowledge points, helps students grasp the knowledge system as a whole, and forms a systematic knowledge network.

2. Mind mapping can improve students' memory and review efficiency. Because the human brain is better at remembering visual information, students can remember and recall what they have learned more quickly and accurately through mind mapping. When reviewing, students can quickly review and consolidate what they have learned just by browsing the mind map.

3. Mind mapping can also stimulate students' innovative thinking. By observing and thinking about the knowledge points in mind map and their relationships, students can discover new laws and problems, and thus put forward new ideas and problems. This is very important to cultivate students' innovative thinking and problem-solving ability.

4. The process of making mind maps is itself a process of deep learning. In the process of making mind maps, students need to constantly review and understand what they have learned and think about the relationship between knowledge points, which will help students deepen their understanding and application of knowledge.