Actually 80 mm is five times AS LONG AS 16 mm. 96 mm is 5 times LONGER THAN 16 mm (i.e., "six times as long as" or "80 mm [which is 5 x 16 mm] longer than").
Using "longer than" to mean "as long as" is a common (and sloppy) practice, but not one we (as measurement specialists) should practice or condone. Bill Potts, CMS Roseville, CA http://metric1.org [SI Navigator] >-----Original Message----- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] >Behalf Of Howard Ressel >Sent: Friday, February 27, 2004 05:16 >To: U.S. Metric Association >Subject: [USMA:28967] 5th grade math lesson > > >My son, a 5th grader, had an interesting math problem the other day. >I'll try to reproduce it from memory, "Jason" has a string 8 cm long, >it is 5 times longer than Mary's string, how long is Mary's string? The >question had to do with remainders and what to do with the remainder. >They have not yet learned too much about fractions and decimals so I do >not believe the answer would include fractions or decimals. I could not >advise my son to give an answer of 8/5=1.6. So, taking advantage of the >metric units I asked my son how many mm in a cm. He figured out it was >10 and I explained how 8 cm is also 80 mm and told him to divide that by >5. He knew how to do that and provided a final answer of 16 mm. Although >I'm not sure that is what the teacher expected it was a great way to >demonstrate how simple metric is. The same problem would have been much >harder to describe if the measurement had been 8 inches. > >Howard Ressel >Project Design Engineer, Region 4 >(585) 272-3372 >
