In fact... multiplication apparently looks something like this: unsum=: 3 :0 digits=. 10 #.inv y multipliers=. (*/\.(#digits)#10)%10 digits*multipliers )
areamodel=: |.@(*&.>/)&unsum x=: +/@,@;@areamodel unsum 123 100 20 3 123 areamodel 456 ┌─────┬────┬───┐ │1200 │150 │18 │ ├─────┼────┼───┤ │8000 │1000│120│ ├─────┼────┼───┤ │40000│5000│600│ └─────┴────┴───┘ 123 x 456 56088 And I guess there's some kind of social issues behind the nature of this kind of standard. It seems a little odd, from my perspective (for example: the boxes are somewhat indicative of the concept of area, but it's very definitely not-to-scale - but being to scale would be silly). But it's still kind of interesting. Thanks, -- Raul On Tue, May 27, 2014 at 7:31 PM, Raul Miller <[email protected]> wrote: > It looks to me like some significant part of the vocabulary of "common > core" math is very similar to that used in J. > > http://commoncore.org/maps/math/video-gallery/array-and-area-models > > Of course, there are some differences also - but perhaps J will be easy > for modern grade schoolers to pick up? > > Food for thought, > > -- > Raul > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
