Judging from the teaching situation, I think this teaching is generally successful, basically achieving the goals of knowledge and skills, process and method, emotion, attitude and values. The successes are as follows:
First, through intuitive operation, express the quantitative relationship and closely follow the meaning of subtraction, so that students can understand arithmetic and master algorithms. In order to let the first-year students understand and master the arithmetic and algorithm of finding the difference between two numbers, intuitive operation is indeed an effective and good method. Ask the students to arrange a row of red sticks and blue sticks one by one, and visually compare who has more and who has less. According to experience, let them "see" more red sticks than blue ones. Then, guide the students to understand how much the red stick is more than the blue stick, in fact, 13 is more than 8. Then, through intuitive operation, after clarifying the quantitative relationship, closely follow the significance of subtraction, so that students can understand how much 13 is greater than 8. If 8 is removed from 13, the formula is 13-8 = 5. In this way, students are guided to realize the goal from "seeing" to "calculating", understand arithmetic and master algorithms.
Second, let students understand arithmetic and master algorithms from several examples. The textbook is limited in space, so students are required to summarize the calculation and algorithm of the actual problem of the difference between two numbers with only one example. In the design, I pay attention to the age characteristics of students and the actual needs of teaching, and gradually guide students to think and sum up through reviewing questions, examples and exercises, so as to truly understand arithmetic and master algorithms. This is obviously in line with the original intention of the editor and the reality of the students.