Am 02.01.2016 um 12:49 schrieb katye2...@gmail.com:
I'm trying to write a python program to find how many trailing zeros
are in 100! (factorial of 100). I used factorial from the math
module, but my efforts to continue failed. Please help.
Using not Python, but math:
Every "0" at the end of 100! represents a multiplication by the factor
10 or the factors 2 and 5.
There are 20 numbers with at least one factor 5.
There are 4 numbers with at least two factors 5 (=25).
There are no numbers with three factors 5 (=125).
There are 50 numbers with at least one factor 2.
So 100! contains 24 factors 5 and even more factors 2.
So 100! contains 24 facotrs 10 and therefore has 24 trailing zeros.
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Robin Koch
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