[math4] Multiplication (discussion)

[Frederick Grose]

2009/3/16 Jason Rock <rockj at rpi.edu>
>
> I would like to throw together a program to teach children multiplication through repeated addition, but since it isn't really the sort of thing that you just throw on flash cards I'd like to get some insight from other people before I start programming.
>
> My idea is given multiplication between x and y.
> Allow keyboard input for x from 0 to ~12
> y depends on a slider that is discrete on 0 to ~12
>
> then display a "matrix" of images where the number of images across is x and down is y
>
> something that looks like
> ****
> ****
> would represent 4*2
> x*y would be displayed somewhere on the app
>
> Does that sound like the sort of thing that would actually help students learn the idea of multiplication?
>
> ===Code Stuff===
> 1) What is the best way to display an "array" of images so that (being vector graphics) the images could re-size to take up as much room as they can?
>
> --Jason

Seems as  this would demonstrate multiplication through repeated
addition, if the incremental changes showed the intermediate sums both
graphically and with numerals and operation symbols.

        +               x
__       0                 0   = 0
**    +2  = 2      x  1  = 2
**    +2  = 4      x  2  = 4
**    +2  = 6      x  3  = 6
**    +2  = 8      x  4  = 8

Some way to display a problem to that the tool can solve if the child
experiments. And then, can let the child use that understanding to
prove that the result is has to true.  Perhaps through repetition and
strange but beautiful cases.

This could also teach the use of multiplication to calculate simple
areas.  (Where is Ed Cherlin and his virtual Cuisenaire rods?)