1. How much do you think 1 gram is in practice? How much does 1 kg weigh? I fully respect the students' existing life experience, and all the cited examples are often contacted or seen by students. Teachers and students work together to prepare enough teaching AIDS, learning tools and articles to mobilize a variety of sensory collaborative learning. Students estimate, weigh, weigh, compare and talk to feel the weight of objects. Students have personally experienced the actual mass of 1 g, a few grams and 1 kg, a few kilograms. This feeling is not instilled by the teacher, but by the students themselves. In the whole teaching process, students participate in learning activities by "doing" rather than just "listening" and "speaking". They not only understood the correct meanings of "gram" and "kilogram", but more importantly, they mastered the general methods of discovering, recognizing and understanding mathematics, and cultivated their exploration consciousness and innovative spirit.

Second, the situation in the construction

In classroom teaching, it is impossible for students to master the balance with their own hands, but students may not see the teacher's demonstration clearly. Therefore, at this time, network resources have given me great help. I let the students see the demonstration process clearly through the demonstration. Because of this experience, the learning process becomes concise and easy to understand.

In traditional teaching, the focus of understanding quality units is generally on units. In the aspect of transformation, the method of teaching memory is often used in teaching. Students can complete the teaching task as long as they remember several commonly used quality units and can switch between them correctly. In this kind of teaching, students often joke after learning the quality unit: a watermelon weighs 3 grams, an egg weighs 50 kilograms, and Teacher Wang weighs 60 grams ... This reflects the serious disconnection between mathematics teaching and real life. The teaching focus of understanding grams and kilograms is based on the concept of "how heavy is 1kg and 1kg", which attaches importance to both mathematical facts and mathematical experience. Therefore, in the "understanding of grams", I repeatedly ask students to weigh, estimate, weigh and find the quality of different objects in life, feel their quality and enrich their mathematical experience. This kind of feeling and experience is not only the basis for further study, but also the necessary skill for "learning to survive" in the future. The concepts of "gram" and "kilogram" are established in students' minds, and gradually formed through students' eye observation, ear listening, brain thinking, mouth expression, hands operation and mental perception, that is, through their own physical experience and experience, they will surely precipitate into students' hearts.

Reflections on the teaching of the second volume of mathematics in the second grade of primary school "Understanding of grams and kilograms"

The teaching of this course seems simple, but it is actually difficult to grasp, mainly because students have already had a perceptual understanding of the concept of quality in their daily life and established a preliminary view of quality. Students have been exposed to quality problems in their lives, but they still lack understanding of quality units. The unit of mass is not as intuitive and concrete as the unit of length, so it can't be observed with eyes, and can only be perceived by muscle feeling. Experience tells me that children's acceptance of knowledge must be a process, from easy to difficult, from less to more, from perceptual to rational, this process is necessary. Experience is irreplaceable by teachers. Therefore, when I design the teaching of grams and kilograms, I pay attention to let students experience in many ways. In view of this situation, my teaching design is to "experience" mathematics. The activity of putting grams and kilograms into experience and establishing specific quality units in experience runs through the whole class. Students operate by themselves, and construct the quality concepts of kilograms and grams in the activities of weighing and estimating. The whole class presents the teaching idea of "weighing it-evaluating it according to experience" and tries to interpret the concept of "knowledge lies in construction" The foothold of instructional design is "experience".

Disadvantages, the whole teaching process of this course takes "experience" as the learning form throughout. Teaching students' ideas, students' reflection-making use of the situation, imperceptibly is the essence of teachers' design and guidance. However, when dealing with students' questions, there are some problems, such as ambiguity, poor handling and inaccurate terminology.

Reflections on the teaching of "Understanding of grams and kilograms" in the second volume of mathematics in the third grade of primary school

I taught this part a few years ago, it was the first time, so I had no experience, just the knowledge in the lecture book, so students often appeared: a person weighs 300 kilograms, an egg weighs 7 grams, and a bag of rice weighs 50 grams-some jokes. Now, I pick up the textbook again, and I only have one idea, that is, how to properly handle this part of the content. Grams and kilograms are the weight units that students come into contact with for the first time, and they should often deal with them in daily life. Therefore, in teaching, I pay attention to the reality of students' life, and arrange investigation activities before class: look for the weight labels of items in the supermarket, look for things marked with weight at home, record what I find and the weight, and pay attention to observing what merchants use to weigh objects. This survey aims to fully develop learning resources, broaden learning channels, enrich students' perceptual knowledge, disperse learning difficulties and stimulate students' interest in learning.

A week later, report to class: What weight units have you known in your life? Do you know the relationship between them? What kinds of scales have you seen? Can you tell us something you are investigating? The weight of an object, so can you name an object with similar weight? Look at each other, say, weigh, weigh and compare-experience, feel and feel the practical significance of grams and kilograms in exchanging reports.

In this series of activities, children really feel that mathematics comes from and serves life, which not only expands their thinking, but also increases the infinite charm of mathematics itself.