Dave, On Thu, 6 Apr 2006 01:41:37 -0400, David VanHorn wrote: > On 4/6/06, kravnus wolf wrote: > > > > 16*15*14*13*......*1 > > > I thought about that, but the number seemed too large somehow. > Thanks! Yes, it *is* very large! Factorials are like that :-) The general case is nPr, which is the number Permutations of r items from a population of n items. It's: n! ---------- (n - r)! When n = r (the case you posed) n - r = 0 and since 0! = 1 it simplifies to n! Cheers, Howard Winter St.Albans, England -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist