"Round hula hoops, round tires, round tables for dinner, and playing games in a circle... Why are these all round?" Jin Haocong, a teacher at Jialvyuan Primary School Education Group in Hangzhou City, Zhejiang Province, used the "round" concept in life "Shape" opens the lesson "Understanding Circles".

On March 28, the "Online Teaching and Research" column of the national smart education platform for primary and secondary schools was officially launched. Based on the new curriculum standards, making good use of current teaching materials, and implementing core competencies, and taking the overall teaching of the "Circle" unit of primary school mathematics as a case, the first national collective teaching and research activity was officially launched. Teachers in primary and secondary schools across the country participated in teaching and research through the national smart education platform for primary and secondary schools.

A paper clip, a piece of wool, a rubber band, a compass, and a ruler. How to draw a circle using these tools?

Drawing a circle is the theme task of this lesson for students.

The class became lively, and students began to use the above different tools to draw circles. Some drew circles, and some did not. Why? Students came to the stage to share.

"The rubber band grows longer and shorter, so it's not round."

"The leg of the compass has moved, so it is not round."

"They all have a definite center point and are all equal lengths to the edges, so circles."

…

Jin Haocong guided the students to gradually understand the characteristics of the "circle" during the discussion. He drew a circle with a compass on the blackboard and wrote down the key words of this lesson - "fixed point, fixed length" and "one middle and same length". After students mastered the basic characteristics of circles, Jin Haocong returned to the question at the beginning of the class - why are these round? Guide students to use mathematical thinking to explain phenomena in life.

At the end of the class, Jin Haocong asked the students a question: How to repair incomplete ancient coins? Let students try to explore more complex and difficult practical problems, and extend circle learning from inside the classroom to outside the classroom.

"The entire class materializes, operates, and visualizes the characteristics of a circle in practical activities, allowing students to learn by doing, using, creating, and understanding, making learning more vivid and profound." During the lecture, Yuan Xiaoping, a special teacher in Zhejiang Province and a researcher at the Hangzhou Xihu District Education Development Research Institute, introduced the curriculum design idea, which is not only to expand students' existing knowledge system, but also to pay attention to the leap-forward improvement of children's thinking and cognitive methods.

"The course design of "Understanding the Circle" embodies the three important concepts of the new curriculum standards, focusing on core competencies, structured course content, and overall unit teaching. This is the direction of our teaching and research." In the expert comment session, Professor and Volunteer of Northeast Normal University Ma Yunpeng, a member of the educational mathematics curriculum standard revision group, said that teaching and research should study a certain typical unit and draw inferences from one example to solve more problems.

In this national collective teaching and research, many teachers and teaching researchers asked questions, and the experts patiently answered them.

"Why not give strict definitions of diameter and radius in class?" asked a teacher in Xiongan New District.

"We need students to understand mathematical concepts through a large number of activities and experiences, rather than mechanically memorizing definitions. We need to be slower and not in a hurry." said Wu Zhengxian, a senior teacher at the Beijing Academy of Educational Sciences and a member of the compulsory education mathematics curriculum standard revision group.

“After the new curriculum standards are released, as a provincial teaching researcher, how should we help implement the core competencies and overall unit teaching of the new curriculum standards?” asked a teaching researcher in Xinjiang.

"We use the method of mixing strong and weak schools in the region to conduct group training, and then focus on presentations and on-site course modifications to promote overall unit teaching improvement." Yu Lingping, a researcher at the Hangzhou Xihu District Education Development Research Institute, said.

"What is a good class? The bell rings, and the thoughts and feelings are not finished." Wu Zhengxian said, "What is good teaching and research? Teach and study, go into the classroom more, and practice hard in the classroom , study real problems, and work with front-line teachers to improve research and practical abilities.”

"Children in the heart" and "learning in practice"... Two hours passed quickly. The first national collective teaching and research activity was coming to an end, and there were still messages from teachers and teaching researchers on the screen.