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 Thread: Mathcounts Marathon View Single Post
 08-01-2007 #23 Sillysidley   Join Date: Oct 2006 Posts: 822 Well, 2-9 can all be made (obviously) and you can get any any number higher by adding multiples of 10 (by adding 5s) so 1. Find $\frac{1}{1*2}+\frac{1}{2*3}+\frac{1}{3*4}+...+ \frac {1}{499*500}$ Oh, and if anyone cares, I meant to ask whats the largest number that must be a factor of any four consecutive odd numbers. (Three is too simple.) __________________ . Last edited by Sillysidley; 08-01-2007 at 08:52 PM..