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Forgotten Number

I have forgotten the number of the combination of the lock on my briefcase. I did have a method for remembering it...

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Powerful Factorial

6! = 6 x 5 x 4 x 3 x 2 x 1. The highest power of 2 that divides exactly into 6! is 4 since (6!) / (2^4 ) = 45. What is the highest power of two that divides exactly into 100!?

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Trailing Zeros

Weekly Problem 13 - 2009
How many zeros does 50! have at the end?

Factoring Factorials

Age 11 to 14 Challenge Level:

Find the highest power of 11 that will divide 1000! exactly.

[Factorial 1000, written 1000!, is the product of the first 1000 whole numbers 1 x 2 x 3 x ... x 1000]

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