“插空法”应用系列樊友年（湖北公安一中４３４３００）解排列组合题，总是觉得没有理想的解答模式，但很多问题只要加强分析类比和归纳，仍然有规律可循，收到多题一法，一法多用的效果．所谓“插空法”，是指先排定某些元，再用余下的元插空的排法，这是大家很熟悉的方... “Interpolation method” application series Fan Younian (Hubei Public Security No. 434300) solves the problems of arrangement and combination, and always feels that there is no ideal answer mode. However, as long as the analysis of analogy and induction is strengthened in many problems, there are still rules to follow and many questions may be received. Law, a multi-purpose effect. The so-called “interpolation method” refers to the arrangement of certain elements first, and then use the remaining elements to insert the empty row of methods; this is a method that everyone is familiar with...