document.write( "Question 1111875: Find the number of trailing zeroes in the product of the first n factorials \n" ); document.write( "

Algebra.Com's Answer #726911 by ikleyn(52908) $\"\"$ $\"About$

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document.write( "Calculate the highest degree of 5 in the product: it will give you the number of zeroes.\r\n" );
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document.write( "The highest degree of 5 is equal to\r\n" );
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document.write( "[n/5] + [n/5^2] + [n/5^3] + . . . + [n/5^m],\r\n" );
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document.write( "where [x] means the \"integer part\" of the number x  (do not ask me what is it - you must know it); \r\n" );
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document.write( "the index \"m\" is the highest degree the number    still divides n.\r\n" );
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