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Subject: overboad on decimals
From: Gordon Talge (gtalge@XXX.XXX)
Date: Sun Jul 25 1999 - 15:13:54 EDT
I get this kind of stuff from my students all the time.
Example: Find the area of a circle with a measured radius of 6.2 inches.
Ans: 120.7628216 instead of 120.8 sq inches.
The kids seem to think that the calculator is some kind of
"math god" and that what ever it spits out is the right answer.
The hardest thing to teach them is " what is a reasonable answer for
your measurements and how to round". One example that always throws them
is this:
1.4
1.4
+ -----
2.8 rounds to 3.0
but, 1.4 rounds to 1.0 and 1.0
1.0
+ -----
2.0
--- Gordon
,,,
(. .)
+-----------------------ooO-(_)-Ooo----------------------+
| Gordon Talge WB6YKK e-mail: gtalge@XXX.XXX |
| Department of Mathematics QTH: Loma Linda, CA |
| Aquinas High School Lat. N 34° 03.1' |
| San Bernardino, CA 92404 Long. W 117° 15.2' |
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