"Mathematics Wide Angle" is a newly added unit in the experimental textbook of compulsory education curriculum standards since the first volume of the second grade, and it is a new attempt made by the new textbook in infiltrating mathematical thinking methods into students. The thinking method of permutation and combination is not only widely used, but also the knowledge base for students to learn probability and statistics, and it is also a good material for developing students' abstract ability and logical thinking ability. This textbook has made some efforts and explorations in infiltrating mathematical thinking methods, presenting important mathematical thinking methods through the simplest examples in students' daily life.

The textbook example 1 shows different two digits through the different arrangement order of two cards, which belongs to arrangement knowledge. Example 1 gives a picture of students placing two digits with digital cards. Students can study in groups, and then exchange their experiences in card release in groups: how to ensure that there is no repetition or omission. The textbook is based on students' familiar and interesting life scenes, and pays attention to infiltrating these mathematical thinking methods into students, putting learning activities in simulated scenes, providing students with opportunities for operation and activities, initially cultivating students' awareness of orderly and comprehensive thinking, and laying the foundation for students to learn combinatorial mathematics and probability statistics in the future.