----- Original Message -----
Sent: 05 Oct 17,Monday 16:56
Subject: [USMA:34930] Re: a prominent
ratio in SI
As usual, legitimate applications can be found for common fractions
but they are usually in technical applications that only specialists need to
know. Would you want a 6th grade child to have to do arithmetic involving the
fraction
1/(299 792 458) ?
How about subtracting it from 1/273.16
(which is another ratio used in the fundamental definitions of SI units -- for
thermodynamic temperature unit, the kelvin).
Can anyone propose ANY
situation where these two ratios would need to be used in the same arithmetic
operation? (Of course not!)
The need for ratios in technical situations
does not make it necessary to teach the arithmetic of common fractions to poor
little 6th grade children.
No, Bill, I'm not advocating that at all. I mentioned
this only as a continuation of the discussion about the usefulness of ratios
in mathematics. I guess I should emphasize that I mean mathematics beyond the
introductory level. And, as I also said, I personally could have done without
trying to interpolate on a ruler among fourths and eighths of an inch as a
child---or even now, occasionally, as an adult.
