
Re: Simplifying Algebraic Expressions with Subtracted Expressions
Posted:
Nov 14, 2013 5:16 PM


Imagine the problem without knowing algebra. When we do elementary word problems prior to knowing algebra we don't "set them up", do we? I am just saying that you can extend that nonsettingup further than what average arithmetic word problems require. It is hard to see it now that we know algebra.
Are you saying that in elementary word problems there is a mental manipulation of {x}? I always viewed it as straightforward literal realization of an arithmetic computation.
I guess we would have to ask her, but that she wrote the solution as just an arithmetic computation makes me believe that this was a (hard) 5th grade word problem, rather than an (easy) 7th or 8th grade one.
Bob Hansen
> On Nov 14, 2013, at 3:56 PM, Joe Niederberger <niederberger@comcast.net> wrote: > > R Hansen says: >> The trick is reading the Ma problem directly into the coefficient (3/5  1/4(13/5)) in one pass > > I'm not arguing that your interpretations are not just fine  I just wonder if that's what she meant. She seems to be saying there is no manipulation of "the unknown quantity" (x) in an algebraic fashion, either mentally or on paper. I'm skeptical. > > The closest I can think of would be to set it up as a proportion type problem right away: > > x / 200 = 1 / (3/5  1/4(13/5)) > > (Which is similar to your idea, I think.) > > Cheers, > Joe N

