how many zeros at the end of factorial 25??

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Number of zeros is identified by number of 10s that 25! can be divided by

10 = 2*5

So, we just have to look at how many pairs of 2 and 5 can we make in factors of 25!

As 2s are abundant in 25!: 2, 4, 6, 8, 10 … 24

% would be the limiting factor and we simply look at the number of 5s:

5 - 1

10 - 1

15 - 1

20 - 1

25 - 2

Total number of 5s in the prime factorisation of 25! = 1+1+1+1+2 = 6

These six 5s can be multiplied with six 2s and give six 10s

Therefore, the answer would be 6 zeros

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thnks

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by error

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