The first lesson is classification and arrangement, and the first lesson of Unit 3 of Mathematics in the second volume of the first grade of People's Education Press. This lesson begins with the classification of candy by color, and understands the importance of classification. Then import from the balloon of the textbook, how to divide the data according to the shape, and clarify two ways to record the data (pictogram and table), and then let the children divide the data according to the color and record the data with white paper. Then use the method of dividing fruits in textbooks to consolidate the two classifications. Finally, the importance of sorting is introduced with life examples.

In this class, the process is smooth, the knowledge points are broken, the classroom norms are mature, and children can basically master the classification and sorting of data. But if I have a class, I will let the first student in each column observe a bag of candy with many colors, and let the last student record the data he hears to see which column conveys the most accurate information and clarify the meaning of probability. Then compare the methods of recording data and extract two forms of recorded data. Compare the two tables and say, if I want to know who has the most, which way would you choose? If I wanted to deliver information quickly and completely, which way would you choose? Let's talk about dividing balloons first. How do you want to send me a message? Ask the students to classify by color or shape, show two standard classifications, and ask, which color balloon has the most, which picture should I see? Finally, summarize the content of this lesson.

The second class is the comprehensive practice of the fourth grade of People's Education Press. The teacher started with a game with the students and threw two dice. How many possibilities are there for the sum of points? 1 1 species! Now, both sides will participate in the game. One party has six numbers of1.2.3.4.1.12, and the other party has five numbers of 5.6.7.8.9. 10. Choose a referee, choose a representative to play, and play at the same table. It is found that the side with five numbers wins more. Why? After sorting out the 36 possibilities one by one, it is found that there are 24 possibilities in five numbers. Then judge how to throw two dice fairly through the game of the little judge. During the whole period, small probability events are also possible events.

In this class, the teacher is humorous and the classroom atmosphere is rich. What did the child learn in this class when I sat down to meditate? Throw dice? No! Isn't introducing probability the most important thing? Through the type of possibility, the probability that the sum of points is 5.6.7.8.9 is obtained by using 24÷36. If the probability is large, the probability of this event can be predicted. The existence of probability is to better predict the occurrence of future events. Of course, accidents are inevitable. So, in my opinion, the focus of this lesson is not only to learn to roll the dice, but also to understand what is the use of probability, where is it besides rolling the dice?