2006年,北京市数学高考试卷(理工农医类)中出现一道概率计算问题.在与一些中学数学教师交流该问题时,我们发现多数数学教师倾向于用类似于“计数的乘法原理”作为解释概率相乘的依据.近几年来,在大学概率课的教学中,我们也发现许多学生出现过类似的问题,因此,我们认为有必要对? In 2006, a probabilistic computational problem occurred in the Beijing Mathematics Entrance Examination (Science, Engineering, Agriculture and Medicine). When communicating this with some middle school math teachers, we found that most math teachers tended to interpret “multiplication as a counter” Basis for Probability Multiplication In recent years, in the teaching of university probability classes, we also found that many students had similar problems. Therefore, we think it is necessary?