Description
Warning: Not all numbers in this problem are decimal numbers!
Multiplication of natural numbers in general is a cumbersome operation. In some cases however the product can be obtained by moving the last digit to the front.
Example: 179487 * 4 = 717948
Of course this property depends on the numbersystem you use, in the above example we used the decimal representation. In base 9 we have a shorter example:
17 * 4 = 71 (base 9)
as (9 * 1 + 7) * 4 = 7 * 9 + 1
10 7 4 9 7 4 17 14 12
6 2 4
原文地址：http://blog.csdn.net/a576699534/article/details/43672815
