Primary school textbooks divide the learning content of geometric figures into several stages: the initial understanding of three-dimensional figures-the understanding of plane figures-the measurement and calculation of plane figures-the re-understanding of three-dimensional figures-the measurement and calculation of three-dimensional figures. The textbooks are arranged in the order of "three-dimensional graphics-plane graphics-three-dimensional graphics", which enables students to understand the learning ideas from the whole to the part and then to the whole, and also clarifies the relationship between plane graphics and three-dimensional graphics. In this regard, I think teachers should pay attention to students' imagination, hands-on operation, observation, exploration and summary in teaching, so that students can learn geometry knowledge from shallow to deep and find the connection between shapes, thus developing spatial thinking.

First, pay attention to the forms in life and make mathematics come alive.

Mathematics comes from and serves life. Teachers should combine teaching materials and combine geometric figures that can be seen everywhere in life with the knowledge they have taught. In this way, students can acquire mathematical knowledge unconsciously.

1. Attach importance to intuitive operation. Students are the masters of learning, let them take the initiative to participate in mathematics activities, and get to know geometric figures through imagination, hands-on, observation and preliminary understanding.

For example, when teaching "Understanding Corner", I introduced the new lesson like this: The red scarf is the symbol of the Young Pioneers, let the students talk about what shape the red scarf is; Then use multimedia courseware to show red scarf, five-pointed star, scissors and so on. Let the students find the corner in the picture. Then let the students find a corner in the classroom. I use this lead-in method to attract students' attention, stimulate students' interest in learning, and let students have an intuitive understanding of the diagonal.

2. Pay attention to hands-on operation. Curriculum standards point out that hands-on operation is one of the important ways for students to learn mathematics. Hands-on operation not only enables students to strengthen the connection between mathematics and life, but also enables students to learn mathematics knowledge through independent exploration before reaching the level of abstract thinking.

For example, when teaching "circumference", I ask students to measure the circumference and diameter of a circle in class. After measurement, students found that the size of a circle is related to the length of radius or diameter, but what is the specific relationship? Because students have learned the knowledge of square tangent circle, they guess that the circumference of a circle is less than four times the diameter. I will ask students to measure the circumference and diameter of a circle. Through group observation and communication, the students found that the circumference of each measured circle, big or small, is more than three times its diameter. I introduce the knowledge of pi and guide students to understand the circumference step by step through their own efforts.

Second, pay attention to the transfer of learning methods and build a knowledge system.

Mathematics knowledge is closely related. In teaching, teachers should pay attention to the connection of knowledge, rationally use transformation ideas and guide students to explore new knowledge with old knowledge.

For example, when exploring the area of a circle, the teacher can ask the students: "In the past, I studied the area of a straight line graph, but today I studied the area of a curved line graph. Can you convert a circle into a learned figure? How to convert? " Teachers should help students explore ideas, give them enough time and space, let them draw a picture, fold a picture, cut a picture and spell it, and then let them go through the process of "guess-operate-deduce" through observation, inquiry and discussion. After the teacher's guidance, some students found that the circle can be cut into several small pieces and then put together to make a parallelogram or rectangle. Through thinking, students think that spelling a rectangle is easier to understand, because the semi-circumference of a circle is equivalent to the length of a rectangle, the radius of a circle is equivalent to the width of a rectangle, and the area of a rectangle is equal to length × width, so the area of a circle = semi-circumference (C/2)× radius (r)=2πr/2×r=πr2.

Third, pay attention to multimedia dynamic demonstration and optimize teaching effect.

1. From plane to three-dimensional, stimulate students' interest in learning. Pupils are curious, eager to learn and like to operate, but spatial thinking is in the primary stage and intuitive thinking is still dominant. In teaching, teachers should attach importance to hands-on activities, and operate, observe and discuss activities throughout the teaching, so that students can deepen their experience, master knowledge and cultivate their skills through practical activities such as discovery, touch and comparison. However, it is difficult to complete the above-mentioned series of activities with high quality only by hands-on operation. We should use multimedia to turn static teaching materials into dynamic teaching content, abstract into concrete, flat into three-dimensional, and make teaching vivid, thus stimulating students' interest in learning.

For example, when teaching "Understanding Cylinders", I first show a rectangle and a square with multimedia courseware, and then rotate around one side of the rectangle to form a cylinder; Taking one side of the square as the axis, a circle will form a cylinder. After students have a preliminary understanding of cylinders, I asked them to give examples to illustrate which objects in life are cylinders and talk about their characteristics. In the process of demonstrating with multimedia courseware, the connection between plane graphics and three-dimensional graphics is communicated, and at the same time, students' interest and enthusiasm in learning are fully mobilized, and their spatial thinking is developed.

2. Stimulate students' thirst for knowledge and cultivate students' spirit of exploration. For example, when deducing the formula of circular area, some students folded the circular paper in half four times, eight times, 16 times ... and divided it into eight parts, 16 parts, 32 parts ... In order to let students understand the mathematical idea of limit, I asked, "Can the folded figure be more like a parallelogram?" When students can't continue origami, I use multimedia courseware to show it (starting with 4 copies and gradually increasing the number of copies). The more copies there are, the closer the figure is to a parallelogram. After dividing the circle into 128, the figure looks like a rectangle. Displaying teaching content through multimedia courseware can make up for the lack of hands-on operation and imagination, and help students to further perceive that "the more the average number of copies, the more the figure looks like a parallelogram or rectangle". Finally, with the help of multimedia courseware, the students successfully deduced the area formula of the circle.

Fourth, pay attention to after-class exercises and cultivate students' application consciousness.

When students master the learning methods, teachers should let students do basic exercises to improve their ability to solve practical problems.

1. Application of basic knowledge. The simple exercise is to solve problems directly with formulas. This kind of exercise is aimed at all students, which can enable most students to consolidate their basic knowledge and enable a few students with learning difficulties to succeed.

For example, after teaching Understanding Triangle, I showed the exercises: (1) A triangle has () sides, () angles, () vertices and () heights; (2) The length of each side of a triangle is equal. Its circumference is 45 cm, and how long is its side?

2. Solve practical problems. Curriculum standards emphasize the cultivation of students' application consciousness. When faced with practical problems, students can take the initiative to try to solve problems from the perspective of mathematics. Therefore, students should have the ability to solve practical problems after learning a geometric figure.

For example, after learning Calculation of the Area of a Circle, I showed the exercise: (1) A circular open space with a diameter of 20 meters and a turf 8 yuan per square meter. How much does it cost to cover this circular clearing with turf? (2) There is a circular flower bed with a diameter of 6 meters in the community, surrounded by fitness stones and a path with a width of 2 meters. What is the area of this path?

In a word, there are many teaching strategies for geometric figures, but no matter which one, it is a good teaching strategy as long as it can stimulate students' interest in learning, improve their enthusiasm for learning and help cultivate their thinking ability. Only when teachers use appropriate teaching strategies can students' interest in learning soar and the teaching effect be ideal.