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December 18, 2014

December 18, 2014

Posted by **Brenda** on Thursday, January 10, 2013 at 9:37pm.

- math -
**Reiny**, Thursday, January 10, 2013 at 10:26pmwe get a zero when we multiply be a number ending in either 2 and 5 or a 10

at the end of 5! --- one zero

at the end of 10! -- two zeros

at the end of 15! -- 3 zeros

at the end of 20! -- 4 zeros

at the end of 25! -- 5 zeros

e.g.

10! = 10x9x8x7x6x5x5x3x2x1

= 2x5x3x3x2x2x2x7x3x2x5x2x2x3x2

= (2^8 x 5^2) x 3^4 x 7

= 6400 x 567 --- ending in 2 zeros

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