Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: Permutations & Combinations
Replies: 1   Last Post: Jan 9, 2005 5:49 PM

 Kevin Karplus Posts: 190 Registered: 12/6/04
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, easy-to-understand 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
(Senior member, IEEE) (Board of Directors, ISCB)
life member (LAB, Adventure Cycling, American Youth Hostels)
Effective Cycling Instructor #218-ck (lapsed)
Affiliations for identification only.

--
submissions: post to k12.ed.math or e-mail to k12math@k12groups.org
private e-mail to the k12.ed.math moderator: kem-moderator@k12groups.org
newsgroup website: http://www.thinkspot.net/k12math/
newsgroup charter: http://www.thinkspot.net/k12math/charter.html