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)

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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

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