Well, they can make *you* think. In the December talk to a grade 7 class I told you about<http://www.jsoftware.com/pipermail/chat/2011-December/004546.html>, a student asked about order of operations. It surprised me that he asked that because at that point I had not introduced enough notation for the order of operations to matter.
I'd subsequently gave a 40 minute talk to a grade 9 class. It made me realized that the grade 7 class was special (showed much more interest, asked more interesting questions, etc.). The grade 9 class mostly sat in silence until I posed the Monty Hall problem<http://www.jsoftware.com/jwiki/Essays/The_Monty_Hall_Problem>in the last 10 minutes. I was flabbergasted when the classproceeded to argue whether a car or a goat was more desirable ... I'll post the ijx transcript from the grade 9 presentation in the next few days. On Fri, Feb 3, 2012 at 11:16 AM, km <k...@math.uh.edu> wrote: > Friends, you can lead a freshman to an idea but you can't make him think. > > Sent from my iPad > > > On Feb 3, 2012, at 1:03 PM, Raul Miller <rauldmil...@gmail.com> wrote: > > > I liked the reference which Roger Hui posted: > > http://www.jsoftware.com/papers/EvalOrder.htm which points out some of > > the ambiguities in PEMDAS. > > > > -- > > Raul > > > > On Fri, Feb 3, 2012 at 1:55 PM, Devon McCormick <devon...@gmail.com> > wrote: > >> You could also highlight the difference in complexity between the > baroque - > >> http://en.cppreference.com/w/cpp/language/operator_precedence - and the > >> simple - "right to left". > >> > >> On Fri, Feb 3, 2012 at 1:19 PM, Roger Hui <rogerhui.can...@gmail.com> > wrote: > >> > >>> You can point out that when there are 100 functions a hierarchy like > that > >>> is unwieldy. See also Ken's paper from 1966, *Conventions governing > order > >>> of evaluation* <http://www.jsoftware.com/papers/EvalOrder.htm>. > >>> > >>> <http://www.jsoftware.com/papers/EvalOrder.htm> > >>> > >>> On Fri, Feb 3, 2012 at 9:24 AM, km <k...@math.uh.edu> wrote: > >>> > >>>> A big problem for college freshmen is that calculators tell them > 2*3+4 is > >>>> 10 and J tells them 14. With apologies to "South Pacific": they have > >>> been > >>>> carefully taught PEMDAS. > >>>> > >>>> Sent from my iPad > >>>> > >>>> > >>>> On Feb 3, 2012, at 10:44 AM, Michael Dykman <mdyk...@gmail.com> > wrote: > >>>> > >>>>> This may sound trite, but > >>>>> > >>>>> Who is the audience? Everyone who does math, be it for engineering, > >>>>> finance, or middle-school algebra. Interactive J should be > >>>>> approachable for a 10 year-old and would be a huge improvement over > >>>>> the calculators and spreadsheets in current use. > >>>>> > >>>>> What do they already know about J? Nothing or less. While I am > >>>>> occasionally surprised by the extent that J is used among very senior > >>>>> financial types, it is a fact that J remains deep in obscurity within > >>>>> the IT industry. I can't imagine that the picture is any clearer > among > >>>>> educators. > >>>>> > >>>>> What the want to know is how to do basic math with the console. What > >>>>> they need is enough of a foundation to begin exploring complex > >>>>> relationships. > >>>>> > >>>>> I agree, Khan Academy provides an excellent model. If we (as a > >>>>> community) were ever fortunate enough to have Khan produce some > >>>>> introductory materials, usage would explode. > >>>>> > >>>>> Having said that, shouldn't this thread be migrated to Chat? > >>>>> > >>>>> - michael dykman > >>>>> > >>>>> On Fri, Feb 3, 2012 at 11:02 AM, Dan Bron <j...@bron.us> wrote: > >>>>>> Hmm. I could do a basic intro to J course at one of the NYC JUGs. > If > >>>> we > >>>>>> broadcast & record it, we could then post it on youtube. > >>>>>> > >>>>>> The question is: who is the audience? What do they already know > about > >>>> J? > >>>>>> What do they want to know? > >>>>>> > >>>>>> -Dan > >>>>>> > >>>>>> -----Original Message----- > >>>>>> From: programming-boun...@jsoftware.com > >>>>>> [mailto:programming-boun...@jsoftware.com] On Behalf Of William > >>>> Tanksley, Jr > >>>>>> Sent: Friday, February 03, 2012 10:43 AM > >>>>>> To: Programming forum > >>>>>> Subject: Re: [Jprogramming] Demise of @ and [: debate > >>>>>> > >>>>>> I'd love to see a youtube class on J. I'd download every episode as > it > >>>>>> aired to my phone and watch it on the train, using my computer to do > >>>>>> experiments and take notes. That's what I do with "njwilberger" > >>>>>> rational trig and hyperbolic geometry lessons. > >>>>>> > >>>>>> -Wm > >>>>>> > >>>>>> On Fri, Feb 3, 2012 at 6:57 AM, Skip Cave <s...@caveconsulting.com> > >>>> wrote: > >>>>>>> A methodical approach to teaching J might be to group the > primitives > >>>> into > >>>>>>> groups of similar functionality. Order these groups by complexity > >>>> (simple > >>>>>>> to complex), as well as perhaps ranking them by familiarity with > >>>>>>> already-learned concepts from traditional math classes, most > familiar > >>>>>>> first. > >>>>>>> > >>>>>>> With a learning sequence defined, spend a class on each group of > >>>>>>> primitives, starting with the simplest and most familiar functions > >>>> (+-*%, > >>>>>>> or perhaps = =. =:), and progress to the most complex and > unfamiliar > >>>>>>> functions.You should probably start with direct execution, and > >>>> introduce > >>>>>>> verb creation after a few classes on basic primitives. Some class > >>> time > >>>>>>> should be spent on how to read and understand the vocabulary > >>>> definitions. > >>>>>>> > >>>>>>> Homework for each class would focus on usage of that current > classes' > >>>>>>> primitives, with previously-covered primitives thrown in for good > >>>> measure. > >>>>>>> The homework problems should be constructed to not require > primitives > >>>> that > >>>>>>> haven't been covered yet (though nothing would prevent an advanced > >>>> student > >>>>>>> from looking ahead and trying them). > >>>>>>> > >>>>>>> It would be interesting to create an online J class, much like the > >>> Khan > >>>>>>> Academy on youtube. In fact, if you really wanted to introduce J to > >>> the > >>>>>>> masses, create a math tutorial that follows and supports Khan's > math > >>>>>>> tutorials, using J as the tool. This would be similar to Iverson's > >>>>>>> "Concrete Math Companion" which follows 'Concrete Mathematics' > >>> (Graham, > >>>>>>> Knuth, and Patashnik (GKP)). > >>>>>>> > >>>>>>> Just a thought.. > >>>>>>> > >>>>>>> Skip > >>>>>>> > >>>>>>> > >>>>>>> On Fri, Feb 3, 2012 at 2:27 AM, Linda Alvord > >>>>>> <lindaalv...@verizon.net>wrote: > >>>>>>> > >>>>>>>> I agree, Don. I really was using a post from Roger because I find > >>> his > >>>> the > >>>>>>>> most difficult to untangle. This thread was a good one to explain > my > >>>> new > >>>>>>>> thoughts about @ and [: > >>>>>>>> > >>>>>>>> My challenges are topics I might use to teach high school seniors > >>>>>> studying > >>>>>>>> precalculus, probability and statistics. They are similar to old > APL > >>>>>>>> contests I invented while I was teaching APL - to get better with > >>> the > >>>>>>>> language myself. However, I'm not sure what would work in classes > >>>> these > >>>>>>>> days. > >>>>>>>> > >>>>>>>> At least I'm having fun with the readers of the forum. J is even > >>>> becoming > >>>>>>>> fun to use! > >>>>>>>> > >>>>>>>> Linda > >>>>>>>> > >>>>>>>> -----Original Message----- > >>>>>>>> From: programming-boun...@jsoftware.com > >>>>>>>> [mailto:programming-boun...@jsoftware.com] On Behalf Of Don Guinn > >>>>>>>> Sent: Friday, February 03, 2012 12:04 AM > >>>>>>>> To: Programming forum > >>>>>>>> Subject: Re: [Jprogramming] Understanding C. , A. > >>>>>>>> > >>>>>>>> Might want to get beginners a little comfortable with J before > >>> showing > >>>>>> them > >>>>>>>> C. and A. > >>>>>>>> > >>>>>>>> On Thu, Feb 2, 2012 at 7:56 PM, Linda Alvord < > >>> lindaalv...@verizon.net > >>>>>>>>> wrote: > >>>>>>>> > >>>>>>>>> I am rethinking my concern with @ and [: and am leaning > toward > >>>>>> using > >>>>>>>>> explicit definitions as a way of teaching J to beginners as a > >>>> natural > >>>>>>>>> mathematical language. > >>>>>>>>> > >>>>>>>>> Some of the programmers responding to the forum think in idioms > and > >>>> use > >>>>>>>> @ > >>>>>>>>> happily. > >>>>>>>>> > >>>>>>>>> f > >>>>>>>>> <:@-@[ C.&.|. ] > >>>>>>>>> i > >>>>>>>>> -@#@[ |. C. > >>>>>>>>> k > >>>>>>>>> <@i.@-@>:@[ C. ] > >>>>>>>>> > >>>>>>>>> 0thers favor the tacit approach with lots of [: > >>>>>>>>> > >>>>>>>>> g > >>>>>>>>> ] C.&.|.~ [: <: [: - [ > >>>>>>>>> h > >>>>>>>>> [: |. ([: <: [: - [) C. [: |. ] > >>>>>>>>> j > >>>>>>>>> C. |.~ [: - [: # [ > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> Both styles are appropriate and I should not suggest one way or > the > >>>>>>>> other. > >>>>>>>>> Many of you have suggested this. > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> We are looking for a simple way to introduce J to beginners. In > >>> my > >>>>>>>>> opinion > >>>>>>>>> we would introduce J as a mathematical language for solving > >>> problem. > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> I am suggest starting with expressions that produce desired > >>> results. > >>>>>>>>> Developing from right to left may come naturally. > >>>>>>>>> > >>>>>>>>> (<:-3 6)C.&.|.'abc*ef*g' > >>>>>>>>> **abcefg > >>>>>>>>> > >>>>>>>>> The next step is making explicit functions indicating if the > >>> intended > >>>>>> use > >>>>>>>>> is > >>>>>>>>> monadic or dyadic. There is no use of @ or [: allowed at this > >>>> point. > >>>>>>>>> > >>>>>>>>> g=: 13 :'(<:-x)C.&.|.y' > >>>>>>>>> h=: 13 :'|.(<:-x)C.|.y' > >>>>>>>>> j=: 13 :'(-#x)|.x C.y' > >>>>>>>>> > >>>>>>>>> Now exploring the tacit definitions would be appropriate in some > >>>>>>>>> environments and can be explored an studied in terms of forks and > >>>>>> hooks. > >>>>>>>>> At this special code and common idioms can be explored and timing > >>> of > >>>>>>>>> expressions can be compared. In the end all roads lead to Rome. > >>>>>>>>> > >>>>>>>>> 3 6 f 'abc*ef*g' > >>>>>>>>> **abcefg > >>>>>>>>> 3 6 g 'abc*ef*g' > >>>>>>>>> **abcefg > >>>>>>>>> 3 6 h 'abc*ef*g't > >>>>>>>>> **abcefg > >>>>>>>>> 3 6 i 'abc*ef*g' > >>>>>>>>> **abcefg > >>>>>>>>> 3 6 j 'abc*ef*g' > >>>>>>>>> **abcefg > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> -----Original Message----- > >>>>>>>>> From: programming-boun...@jsoftware.com > >>>>>>>>> [mailto:programming-boun...@jsoftware.com] On Behalf Of Linda > >>> Alvord > >>>>>>>>> Sent: Wednesday, February 01, 2012 6:01 PM > >>>>>>>>> To: 'Programming forum' > >>>>>>>>> Subject: Re: [Jprogramming] Understanding C. , A. > >>>>>>>>> > >>>>>>>>> Sorry I missed the version by Arie. Nice! > >>>>>>>>> > >>>>>>>>> 3 6 (i=:-@#@[ |. C.) 'abc*ef*g' > >>>>>>>>> **abcefg > >>>>>>>>> i > >>>>>>>>> -@#@[ |. C. > >>>>>>>>> > >>>>>>>>> j=: 13 :'(-#x)|.x C.y' > >>>>>>>>> j > >>>>>>>>> C. |.~ [: - [: # [ > >>>>>>>>> > >>>>>>>>> 3 6 j 'abc*ef*g' > >>>>>>>>> **abcefg > >>>>>>>>> > >>>>>>>>> Please let me know if you have concerns or modifications as I > plan > >>> to > >>>>>> use > >>>>>>>>> different rules beginning with challenge 6. > >>>>>>>>> > >>>>>>>>> Henceforth I'll have no opinion concerning the merits of @ and > >>> [: > >>>> I > >>>>>>>>> hope > >>>>>>>>> to learn to favor them both gracefully. > >>>>>>>>> > >>>>>>>>> Linda > >>>>>>>>> > >>>>>>>>> -----Original Message----- > >>>>>>>>> From: programming-boun...@jsoftware.com > >>>>>>>>> [mailto:programming-boun...@jsoftware.com] On Behalf Of Linda > >>> Alvord > >>>>>>>>> Sent: Wednesday, February 01, 2012 5:20 PM > >>>>>>>>> To: 'Programming forum' > >>>>>>>>> Subject: Re: [Jprogramming] Understanding C. , A. > >>>>>>>>> > >>>>>>>>> I'm happiest with the explicit version. It shows the arguments > >>> needed > >>>>>> for > >>>>>>>>> the application. > >>>>>>>>> > >>>>>>>>> 3 6 (f=:<:@-@[ C.&.|. ]) 'abc*ef*g' > >>>>>>>>> **abcefg > >>>>>>>>> 3 6 f a=:'abc*ef*g' > >>>>>>>>> **abcefg > >>>>>>>>> > >>>>>>>>> g=: 13 :'(<:-x)C.&.|.y'! > >>>>>>>>> 3 6 g a > >>>>>>>>> **abcefg > >>>>>>>>> > >>>>>>>>> f > >>>>>>>>> <:@-@[ C.&.|. ] > >>>>>>>>> g > >>>>>>>>> ] C.&.|.~ [: <: [: - [ > >>>>>>>>> g=: 13 :'(<:-x)C.&.|.y' > >>>>>>>>> > >>>>>>>>> J provides the ~ which shows up in the tacit version above. > >>>>>>>>> > >>>>>>>>> Then there is h with no ~ and no &. > >>>>>>>>> > >>>>>>>>> h=: 13 :'|.(<:-x)C.|.y' > >>>>>>>>> h > >>>>>>>>> [: |. ([: <: [: - [) C. [: |. ] > >>>>>>>>> 3 6 h a > >>>>>>>>> **abcefg > >>>>>>>>> > >>>>>>>>> Linda > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> -----Original Message----- > >>>>>>>>> From: programming-boun...@jsoftware.com > >>>>>>>>> [mailto:programming-boun...@jsoftware.com] On Behalf Of Roger > Hui > >>>>>>>>> Sent: Wednesday, February 01, 2012 11:26 AM > >>>>>>>>> To: Programming forum > >>>>>>>>> Subject: Re: [Jprogramming] Understanding C. , A. > >>>>>>>>> > >>>>>>>>> Personally, I dislike expressions with multiple uses of ~ as they > >>>> make > >>>>>> my > >>>>>>>>> head spin. > >>>>>>>>> > >>>>>>>>> 3 6 (C.&.|.~ <:@-)~ 'abc*ef*g' > >>>>>>>>> **abcefg > >>>>>>>>> 3 6 (<:@-@[ C.&.|. ]) 'abc*ef*g' > >>>>>>>>> **abcefg > >>>>>>>>> > >>>>>>>>> I much prefer the second over the first. > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> On Wed, Feb 1, 2012 at 8:05 AM, Aai <agroeneveld...@gmail.com> > >>>> wrote: > >>>>>>>>> > >>>>>>>>>> Ah, I see that's a bit like yours David. > >>>>>>>>>> > >>>>>>>>>> Modifying it for 1< #x > >>>>>>>>>> > >>>>>>>>>> 3 6 (C. |.~ -@#@[) 'abc*ef*g' > >>>>>>>>>> **abcefg > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> (from Essays) > >>>>>>>>>> > >>>>>>>>>> 3 6 (C.&.|.~ <:@-)~ 'abc*ef*g' > >>>>>>>>>> **abcefg > >>>>>>>>>> k > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> On 01-02-12 16:47, Aai wrote: > >>>>>>>>>>> Sorry for the noise. You should forget the previous ones I > sent: > >>>>>> they > >>>>>>>>>>> are wrong. > >>>>>>>>>>> > >>>>>>>>>>> It looks like this one is ok: > >>>>>>>>>>> > >>>>>>>>>>> mtf=:_1&|.@C. > >>>>>>>>>>> > >>>>>>>>>>> ]samples=: '*abcef' |."0 1 ~-i.6 > >>>>>>>>>>> *abcef > >>>>>>>>>>> f*abce > >>>>>>>>>>> ef*abc > >>>>>>>>>>> cef*ab > >>>>>>>>>>> bcef*a > >>>>>>>>>>> abcef* > >>>>>>>>>>> > >>>>>>>>>>> > >>>>>>>>>>> ]res=: '*' ([,-.~) "1 samples > >>>>>>>>>>> *abcef > >>>>>>>>>>> *fabce > >>>>>>>>>>> *efabc > >>>>>>>>>>> *cefab > >>>>>>>>>>> *bcefa > >>>>>>>>>>> *abcef > >>>>>>>>>>> > >>>>>>>>>>> res -: mtf&>/"1 (;~I.@:('*'&=))"1 samples > >>>>>>>>>>> 1 > >>>> > >>> ---------------------------------------------------------------------- > >>> For information about J forums see http://www.jsoftware.com/forums.htm > >>> > >> > >> > >> > >> -- > >> Devon McCormick, CFA > >> ^me^ at acm. > >> org is my > >> preferred e-mail > >> ---------------------------------------------------------------------- > >> For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
