Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
NCTM or The Math Forum.



Re: Permutations & Combinations
Posted:
Jan 9, 2005 5:49 PM


In article <v3r2u0dl4v9j4afof0fdfki0jvdi5cup85@4ax.com>, Jerry Beeler wrote: > I've been teaching 9th grade math for so long that ... well ... I think that > Christ was a teen when I started. > > In any case, I'm now faced with some high level math and need a little help. > > I need a good, easytounderstand explanation of "combinations" versus > "permutations" with some example(s). > > Do 'appreciate it.
You can have a group of distinct kids and a (same number) group of distinct tasks (roles in a play, positions on a baseball team, ...). The number of different ways the kids can be assigned tasks is a permutation.
You can have a group of n distinct kids and have to choose a committee of k members (k <= n). The number of ways the committee can be chosen is a combinations "n choose k".
There should be hundreds of examples in any book on applied discrete math, as combinatorics is usually a chapter or two in such books.
 Kevin Karplus karplus@soe.ucsc.edu http://www.soe.ucsc.edu/~karplus Professor of Biomolecular Engineering, University of California, Santa Cruz Undergraduate and Graduate Director, Bioinformatics (Senior member, IEEE) (Board of Directors, ISCB) life member (LAB, Adventure Cycling, American Youth Hostels) Effective Cycling Instructor #218ck (lapsed) Affiliations for identification only.
 submissions: post to k12.ed.math or email to k12math@k12groups.org private email to the k12.ed.math moderator: kemmoderator@k12groups.org newsgroup website: http://www.thinkspot.net/k12math/ newsgroup charter: http://www.thinkspot.net/k12math/charter.html



