Permutation and combination is the primary knowledge of combinatorial mathematics, the basis of learning probability and statistics, and also the widely used mathematical knowledge in daily life. In the textbook of the first volume of the second grade, students have been exposed to a little knowledge of arrangement and combination. Students can find out the number of permutations and combinations of the simplest things through observation, guess and experiment. On the basis of students' existing knowledge and experience, this textbook continues to let students find out the number of things arranged and combined through observation, guess and experiment.

Learning style

1, so that students can find out the arrangement number and combination number of simple things through observation, guess and experiment.

2. Cultivate students' orderly and comprehensive thinking consciousness.

3. Let students feel the application value of mathematics in real life and try to solve problems in real life by mathematical methods.

4. Make students form a good habit of cooperating with others in the activities of counting students, and initially train students to express the general process and results of solving problems.