Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
NCTM or The Math Forum.



Re: nctmldigest V1 #119
Posted:
Aug 10, 1995 12:14 PM


> From: rex@bertha.cqu.edu.au (Rex Boggs) > Date: Wed, 9 Aug 1995 19:48:40 +1000 > Subject: re: el fractions etc
[snip!]
> But what question can you pose where the necessary operation is > dividing, say, 1/4 by 3/5? I used to think there weren't any such > questions, until I read a good response last year (somewhere on the Net..) > > Think of division of fractions another way  > first think of 3 divide 6 = 1/2 as meaning that 3 is 1/2 of 6. Also, > 1/4 divide 2 = 1/8 means that 1/4 is 1/8 of 2, So 1/4 divide 3/5 > becomes ' 1/4 is what part of 3/5?' and the answer is that 1/4 is > 5/12 of 3/5. > > I haven't come across anything better than that.
How about the following:
How many quarterpound bags of rice would you need to buy in order to have 5 1/2 pounds of rice?
(For a very thought provoking article on this subject, I recommend "The Mathematical Understandings that Prospective Teachers Bring to Teacher Education", by Deborah Loewenberg Ball, The Elementary School Journal, Vol 90, No 4, Pg 449466)
DVS



