数字1,2,3,4.能组成多少组数字,举个例1234,1324.
问题描述：
数字1,2,3,4.能组成多少组数字,举个例1234,1324.
答
1234,1243,1324,1342,1423,1432,2134,2143,2314,2341,2413,2431,3124,3142,3214,3241,3412,3421,4123,4132,4213,4231,4312,4321共24种太对了真好。