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From: lseaman@hawk.ulowell.edu (Lyle Seaman)
Newsgroups: comp.edu
Subject: Re: Math tricks, was: Calculators in exams, was: Becoming CAI literate
Message-ID: <5269@swan.ulowell.edu>
Date: 6 Mar 88 01:23:58 GMT
References: <2032@ukecc.engr.uky.edu> <3900008@nucsrl.UUCP> <1988Feb24.224849.928@jarvis.csri.toronto.edu> <24954@cca.CCA.COM> <7301@tut.cis.ohio-state.edu>
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In article <7301@tut.cis.ohio-state.edu> zwicky@pterodactyl.cis.ohio-state.edu (Elizabeth D. Zwicky) writes:
>I was moving the decimal place to get 10% and then multiplying that,
>which math teachers fail because the intermediate steps aren't "right"
>but it sure works.)			

Of course, it IS a mathematically sound way of finding a result:
0.2*y = 0.1*y*2 or 0.15*y = 0.1*y + (0.1*y)/2   etc...
Unfortunately, what passes for "right" among schoolteachers is all too 
often what _they_ say is right, and only that...  This attitude is most
common among schoolteachers who have a poor grasp of the subject matter 
being taught.   I saw it most in elementary school, least in grad school.
--
lyle