perplexus.info :: Just Math : Count the trailing zeros

Count the trailing zeros (Posted on 2021-11-30)

Consider N=82!
How many zeros are there at the end of N?
i. In its decimal form.
ii. In base 9.
iii. In base 11.

No Solution Yet Submitted by Ady TZIDON

Rating: 4.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)

re(2): solution -- answer for base 9 seems wrong

| Comment 3 of 4 |

Of course, the formula for base 9 neglected that 81 is also less than 82. The formula should have included a term for a denominator of 81:

floor((floor(82/3) + floor(82/9) + floor(82/27) + floor(82/81)/2) = 20

Posted by Charlie on 2021-11-30 09:44:34

Please log in:

Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (9)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:


perplexus dot info