The mind map of the third unit of mathematics in the first volume of the fifth grade can be drawn from three aspects: knowledge context, important formulas and laws, and error-prone knowledge points.

1, knowledge context is the basic framework of mind map, which can clearly present the main contents of this unit. In this mind map, we can take fractional multiplication as the central theme, and then according to the content in the textbook.

It is divided into several sub-topics such as the significance of decimal multiplication, the calculation method of decimal multiplication, and the application of decimal multiplication in life. Each sub-topic can be subdivided into more specific sub-topics to form a well-defined knowledge network.

2. The arrangement of important formulas and laws is also an important part of mind map. In this unit of decimal multiplication, students need to master the rules of decimal multiplication, including: decimal point alignment, multiplication with the same number, and all decimalization into one. These rules can be used as sub-themes of mind map and marked in the corresponding knowledge context for students to find and remember quickly.

3. The arrangement of error-prone knowledge points is also crucial. In the unit of decimal multiplication, students may encounter some calculation errors, such as forgetting to carry and moving the decimal point incorrectly. These error-prone knowledge points can be used as sub-themes and marked in the corresponding knowledge context to remind students to pay attention to correction.

Skills of making mind maps;

1. Determine the central theme: Before making a mind map, you need to determine the central theme and use it as the center of the mind map. The central theme should be the main content of this unit or course, or the main problem to be solved. Ensure that the central theme is clear, concise and can cover most of the content.

2. Branch themes and sub-themes: According to the central theme, the content is decomposed into several branch themes and sub-themes. Sub-theme should be an extension of the central theme, while sub-theme should be a further refinement or explanation of sub-theme. Make sure that the logical relationship between theme and sub-theme is clear, so that readers can better understand the content.

3. Use graphics and colors: Graphics and colors are very useful tools in mind maps. Using different graphics and colors can highlight key points, distinguish different themes and sub-themes, and make mind maps more vivid and interesting. For example, boxes with different shapes can be used to represent different themes and sub-themes, or different colors can be used to mark different contents.