1. Guide students to systematically sort out the graphics they have learned, communicate the connections between the graphics, and form a knowledge network.
2. Combining with specific objects or graphics, guide students to learn three-dimensional graphics from different angles, communicate the relationship between three-dimensional graphics and plane graphics, and develop students' spatial concepts.
3. Be able to use the knowledge and skills learned to solve simple problems in daily life and experience the close relationship between mathematics and life.
4. Guide students to exchange and organize knowledge.
When reviewing this part of the content, we should focus on guiding students to re-perceive the characteristics of graphics, so as to strengthen, expand and communicate the links between graphics, and then consolidate them through certain exercises. According to the content characteristics and the age characteristics of primary school students, the textbook is divided into two parts when arranging the review of graphic understanding. The first part is "systematic arrangement, communication and connection", which mainly guides students to systematically arrange the graphics they have learned, communicate the connections between graphics, and form an organic knowledge network of "space and graphics"; The second part is "grasping the characteristics and deepening the practice", which mainly guides students to reproduce the characteristics of various graphics in their minds from three aspects: "line and angle", "plane graphics" and "three-dimensional graphics", and arranges and internalizes them, so as to further consolidate and deepen students' understanding of graphics through some typical exercises.
We can list the graphics that students have learned first; Then guide students to classify these figures, sort out the connections between knowledge contents, and present the connections between knowledge through network diagrams and other forms; Finally, organize students to show their achievements and communicate. The form of knowledge collation is not unique. Teachers should encourage it as long as it is reasonable. For the good works presented by students, teachers should let students introduce the methods of arrangement, and cultivate students' ability of reflection and arrangement of knowledge. In the process of classification, we should pay attention to two points: first, combine the map with its name. Encourage students to draw pictures according to their names (draw three-dimensional pictures under the guidance of teachers), and deepen students' understanding of the relationship between pictures through classification. For example, in the classification of polygons, students may further find that quadrangles and pentagons can be decomposed into several triangles. When reviewing the relationship between three-dimensional graphics and plane graphics, the textbook presents three pictures to remind students to communicate the relationship between three-dimensional graphics and plane graphics from different angles. The first picture presents a cube and communicates from the perspective of "view" to guide students to further understand "face on the body"; In the second picture, the side of the cylinder is unfolded into a rectangle, which is conveyed from the perspective of "the unfolding of three-dimensional graphics"; The third picture shows that the cross section of the cone is triangular, and it communicates from the perspective of "cross section". In teaching, teachers should guide students to study various three-dimensional graphics from different angles and exchange the relationship between three-dimensional graphics and plane graphics. In teaching, we should pay attention to let students operate properly, so as to improve their understanding of what they have learned and accumulate experience in mathematical activities.
For the teaching of lines and angles, the textbook gives four questions to guide students to review and sort out the knowledge of lines and angles. The first question is to guide students to review the relevant knowledge of "straight line, line segment and ray". When teaching, students can draw a picture first and then communicate; You can also compare the student list. The second question is. Guide the students to review the vertical and parallel. When teaching, students can draw a picture first and talk about the basic method to judge whether a straight line is vertical or parallel. The third question guides students to compare the size of angles and review the measurement of angles. In teaching, let students talk about the method of measuring angles, and let each student measure angles with a protractor. The fourth question reviews acute angle, right angle, obtuse angle, right angle and rounded corner.
The topic of consolidation and application should be operated by students themselves.
The course of plane graphics is mainly to guide students to review the understanding and characteristics of plane graphics such as rectangle, square, triangle, parallelogram, trapezoid and circle. When teaching this part of the content, teachers should make clear the teaching objectives and guide students to sort it out according to certain procedures. For example, from the side, special quadrangles include trapezoid and parallelogram, parallelogram includes rectangle, and rectangle includes square. Only one set of quadrangles with parallel opposite sides is a trapezoid, two sets of quadrangles with parallel opposite sides are parallelograms, the opposite sides of a rectangle are parallel and equal, and the four sides of a square are equal. From the point of view, the four corners of a rectangle and a square are right angles and all four corners are equal; Another example is from the perspective of axisymmetric graphics. In these figures, rectangle, square, isosceles triangle, equilateral triangle, isosceles trapezoid and circle are all axisymmetric figures, equilateral triangle and isosceles trapezoid have only one axis of symmetry, rectangle, equilateral triangle and square have two, three and four axes of symmetry respectively, and circle has countless axes of symmetry. When rearranging, encourage students to express their knowledge in appropriate forms.