I remember when I was talking about axisymmetric figures, I arranged for students to cut some plane figures, such as squares, rectangles, parallelograms, circles, triangles, trapeziums and so on. Let students learn to solve problems independently in class: by cutting, folding and spelling, find out which figures are axisymmetric, and there are unexpected surprises in class. Most students verified that the parallelogram is not an axisymmetric figure by folding and cutting, and I am sure there is no problem. I don't believe you. This is the symmetry axis. "The words sound just fell and the students began to talk noisily. Many students say "there is no symmetry axis" without thinking, and some whisper "there is symmetry axis". The two groups of students did not give way to each other. They held each other, but no one raised their hands. I waited patiently and looked forward to it. ...
At that moment, I also froze, thinking, how is this possible? But modular teaching tells me: children should be allowed to speak freely! Express your thoughts and report your gains. So I asked the student to give a demonstration on the platform himself. Alas, not bad! The parallelogram he made does have two symmetry axes. At this time, the students are confused and eager to know the reason.
I strike while the iron is hot, and let the students see the difference between the parallelogram made by the students and everyone's in the form of a group. Everyone is full of interest. Through careful observation and measurement, it is concluded that the two diagonals are its symmetry axes. I'd like to take this opportunity to tell you that the figure he cut is rhombic and axisymmetric, and you'll know later! Generally speaking, parallelogram refers to two groups of quadrilaterals with equal and parallel opposite sides, and is not an axisymmetric figure. I praised JUNG WOO and gave him a small red flag, so that my classmates could learn from him in the future. Applause broke out in the classroom, and JUNG WOO jumped for joy.
Mathematical thinking is the soul of mathematics teaching. In classroom teaching, we should start from students' thinking and cultivate their spirit of solving problems independently. If students make mistakes, don't criticize them, but encourage them to protect their self-esteem and self-confidence. In this way, students not only get intellectual enlightenment, but more importantly, they get spiritual support and emotional satisfaction. In the future, they can express their views, experience the joy of success and creation, and continue to play.