请教一道数学题

bfghdggf

费费宝典中的18题

N!的尾数有六个0, 求N的最小值. 答案是25.

请问大家有什么好方法啊?

himba

in order to make 6 0's in the end of an integer by having a product of bunch of integers, you need 2's and 5's in order to do this:

1*2*3*4*5, this will have one 0 at the end, since it has 2 and a 5;

so u need 5, 10, 15, 20, 25(which has 2 5's) in order to make 6 zeros, u don't have to worry about 2's since u get at least one for every other integer u get...