说明：  验证卡布列克运算。任意一个四位数，只要它们各个位 上的数字是不全相同的，就有这样的规律： 1)将组成该四位数的四个数字由大到小排列，形成由这四个 数字构成的最大的四位数； 2)将组成该四位数的四个数字由小到大排列，形成由这四个 数字构成的最小的四位数(如果四个数中含有0，则得到的数不足 四位)； 3)求两个数的差，得到一个新的四位数(高位零保留)。 重复以上过程，最后得到的结果是6174，这个数被称为卡布 列克数。
(certification Roman computing. A four-digit arbitrary, as long as they all place on the same figure is incomplete, this is the law : a) the composition of the four four-digit figures with 7,10,13, formed by four of the greatest figures of the four-digit; 2) The composition of the four four-digit figures headed arranged by the formation of the four figures constitute the smallest of the four-digit (if 4 contains a few 0, then the less than 4); 3) 2 for the number of poor, received a new four-digit (high-reservations). Repeat the above process, the final result is 6,174, a figure known as the Roman few.)