Effective hands-on practice requires students to be clear about "why to move" and know how to move, all of which require teachers to design operation activities reasonably.

(A) seriously study textbooks

Teachers must fully consider their own teaching objectives, student activities and other issues. "Teach what? When to teach? How to teach? How to help students with learning difficulties? " Wait a minute. When preparing lessons, teachers must accurately grasp the teaching materials and grasp the scientific system and logical structure of the teaching materials; Grasp the key content and non-key content of the textbook; Grasp the difficulties and doubts in the textbook. Then, on the premise of being loyal to and respecting the teaching materials, we will study relevant learning strategies and design various novel activities to make students learn easily, interestingly and effectively.

(2) Carefully select practical materials.

Mathematics studies the quantity and shape of things, not the external characteristics and attributes of objects. Therefore, the standard of choosing homework materials depends on whether homework activities are conducive to promoting students' understanding of activities, whether they can effectively complete teaching tasks and achieve teaching goals, and then consider their life, interest and openness. If teachers think too much about the latter, learning tools may become "toys", which is counterproductive and plays a negative role. In teaching activities, teachers should carefully select and provide materials related to revealing mathematical concepts and principles, which can stimulate students to explore, taking into account factors such as the size and color of materials, and on the basis of studying the characteristics of materials, let students practice freely. For example, when teaching the volume of a cone, the teacher organizes students to experiment in groups. Two groups of experimental materials are provided to each group. A group of hollow cylinders and cones with equal bottoms and equal heights; The other group is hollow cylinder and cone with different base heights. Then let the students experiment in groups with water, sand and other materials to explore the volume relationship between cone and cylinder.

(3) Dig deep into the thinking ability of homework materials.

Mathematics is the gymnastics of thinking. The main way of mathematics learning is not hands-on operation but mathematical thinking. All hands-on operations are a carrier for developing mathematical thinking. In a 40-minute math class, the types and time of operating materials that teachers can use are limited. On the premise of carefully selecting homework materials, we must dig deep into the value of each homework material to make it serve the development of students' thinking to the maximum extent.

For example, in the teaching of "Preliminary Understanding of Fractions", two teachers asked students to prepare square paper. A teacher did this. The teacher said, "Please fold the square paper in half up and down, then fold it in half left and right, and draw out one of them with a colored pen.". Can you tell me how much of this paper is colored? " The students quickly completed the operation according to the teacher's requirements, and quickly said that the colored part was a quarter of this square paper, while the colored part of the students was exactly the same. Namely:

Another teacher did this and said, "Can you divide this square piece of paper into four parts by hand?" ? Colour one of them. How much is the color part of this paper? The students also quickly reached the correct conclusion according to the teacher's requirements, but the students' answers are several:

The same link, the same teaching AIDS, but the classroom effect is quite different. In the new teacher's class, students are just "operators" and square paper is just "props". All activities are carried out under the teacher's question, "the teacher's brain is the student's hand", and the students lack the time and opportunity to think independently. The development of mathematical thinking is limited to the mechanical understanding and application of fractions. In the second teacher's class, the students became "explorers" and the square paper became the "golden hoop" in their hands. Using it to transform different patterns, students' thinking sparks can bloom in these different operations. It is not enough to operate only in teaching. Teachers should also pay attention to the design, guidance and optimization of students' operation activities, give full play to the role of materials, make hands-on operation closely related to mathematical thinking, and have enough gold content, so as to achieve the purpose of real hands-on operation.

Second, seize the opportunity of students' hands-on operation to promote the effectiveness of the operation.

Primary school students' thinking is characterized by the dominant thinking in images and the gradual transition to abstract thinking. In the process of learning new knowledge, they should first observe with their eyes, operate with their hands and describe with their mouths, thus establishing the appearance of things, especially for junior students. According to their age characteristics and cognitive rules, teaching AIDS and learning tools are essential in classroom teaching. However, we can often hear the teacher say something like this at the beginning of the class in order to ensure the classroom order and complete the teaching task: "Put ... (learning tools) in the corner of the table, and don't move, it's more obedient than whose little hand." Learning tools should be tools for children to consciously solve problems when they encounter problems, but now they have become props controlled by teachers. When faced with problems that they can't solve, children choose to wait more and will not take the initiative to try with the tools at hand (unless the teacher has special instructions). Sometimes teachers lead children to practice, and basically arrange the same time first. The teacher first puts forward the operation requirements, and then the students strictly follow the teacher's instructions. On the surface, it looks very orderly, and the students are quite enthusiastic about it. But think about it carefully, why do you want to operate? Is it a demand put forward by students? In fact, in this process, students have no initiative to explore. The whole process is that students perform simple operations and calculations according to the teacher's instructions. The so-called inquiry, students just act as operators. Although it is necessary to arrange a directional guidance link before students begin to operate, it is also important to help students master the correct operation methods, but we must pay attention to the scale, leave appropriate difficulty for students' inquiry, enhance students' willingness to challenge and cultivate students' independent inquiry ability.

Third, create situations to attract students to practice and promote the effectiveness of the operation.

In the process of learning, primary school students often pay attention to it at will. In teaching, teachers should create teaching situations, induce learning motivation, attract students' involuntary attention to participate in learning, and guide students to actively think and explore mathematical problems, so as to achieve the purpose of mastering knowledge and developing intelligence.

For example, when learning "subtraction of abdication within 20 years", the teacher created a shopping situation and asked two people at the same table to play the role of salesman and customer respectively. There were 15 pencils in the shop, and 9 pencils were sold. How much is left? Students use sticks to explore the calculation method. Some open a bundle of sticks and take out 9 sticks, leaving 1 stick. 1 stick plus 5 sticks makes 6 sticks, and there are 6 sticks left. Some took a bundle apart, took out four pieces, made nine pieces out of five pieces and took them away, and finally there were six pieces left. Others counted out nine of them one by one and took them away, and finally got the result. Another example is when the teacher recognizes the number 7 in teaching. The teacher created the scene of seven dwarfs picking fruit in the cartoon Snow White. They picked seven big fruits and took two bags. Guess how they packed it. Stimulated the students' desire for autonomous learning, the students actively used their brains to find ways to replace seven fruits with seven small disks, seven small triangles and seven small sticks, and listed all possible results. Some methods of drawing fruits also had results.