孔子的学生子贡能“闻一以知二”,另一学生颜渊能“闻一以知十”。这两人都得到他们老师孔子的喜爱。因为他们的学习符合孔子一贯主张的“举一反三”的教学思想。所谓“举一反三”的“一”和“三”,并非实数。前者是指学生从老师那里接受到的知识、经验;后者是指学生在已知的前提下推知未知,用孔子的话来说就是“告知往而知来者”。这是对学生起码的要求。如果有这样一个学生:老师告诉他一个方形的东西有四只角,一只角是什么样子的,学生这时还要问其它三只角是什么样子的,那么,他就认为这样的学生 Confucius’s student Son Gong can “smell one to know two” and another student Yan Yuan can “smell one to know ten”. Both of them are loved by their teacher Confucius. Because their study accords with the teaching idea of ​​“giving top priority to oneness and one mind” advocated by Confucius. The so-called “one case” and “three cases” are not real numbers. The former refers to the students received from the teacher knowledge, experience; the latter refers to the known under the premise of students to know unknown, in the words of Confucius is “to inform and know.” This is a minimum requirement for students. If there is such a student, the teacher tells him that a square has four corners and one corner looks like, and the student then asks what the other three corners look like, then he thinks such a student