In the fourth grade, the chapters of unit 1-8 mind map are as follows: The first unit is the understanding of a large number of mind map knowledge (understanding, reading, writing and size comparison within 100 million; ); Unit 2 Mind mapping knowledge hectares and square kilometers; Unit 3 Measurement of mind map of knowledge angle (understanding of line segments, straight lines and rays, understanding, measurement, classification and drawing of angles); Unit 4 mind map knowledge three digits times two digits; Unit 5 parallelogram and trapezoid mind map knowledge (including drawing vertical lines, rectangles and the distance from points to straight lines, etc. ); The knowledge divisor of Unit 6 mind map is the division of two digits (the test sites have the most content and grasp the key points); Unit 7 mind map knowledge bar chart; Optimization of wide-angle problems in Unit 8 mind map knowledge mathematics (mainly to understand three practical application problems: making tea, making pancakes and racing in Tian Ji). The above-mentioned unit test sites will be drawn into a series of mathematical mind map lists with each chapter, and some unit error-prone analysis questions will be attached to the content with less knowledge points, so that students can truly understand and thoroughly understand the relationship between each unit test site in the first volume of grade four, thus consolidating their knowledge of mathematical theory.