> The replacement for a $100 problem is to buy students iPads and use an app and touchscreen?When put exactly that way, yes that sounds silly.
But what about an app and a stack of much cheaper tablets? Not one per child but a pool for the school which are available to use in lesson time, exam time, and for the less well-off students to be borrowed for homework. Those that have their own Android tablet can just use their own and run the app on that, just needing a school one for exams (where they would not be allowed their own because they could bring notes into a closed-book exam).
For exam use they'd need to be locked down but that should be easy enough. Require that all students use a school provided one (so they can't hide notes and other such on their own devices) and re-image each before the exams start (so yes, some admin time to factor in here) with a base OS plus the desired app and all wireless locked off.
I mentioned Android above for cheapness mainly, if you are going to target one platform then for this use the one you can get the least expensive units for should win. Having said that, you don't need to go the native app route: build it in JS and you can run it on any device. For what the students will be needing even those cheap god-awful-slow tablets will cope quite nicely unless your JS and DOM manipulations are grossly inefficient. For the locked-down situation in an exam room "run" the app from local files and use the local storage options in the browser if you need to maintain state.
There would be an up-front cost (buying a job lot of tablets initially) and ongoing maintenance (a rolling program of replacing them as they break and some admin time updating/resetting them as needed) but you can get easily get 7" tablets for less than $50 each as single units and that price should drop when buying in bulk. For a smaller device something like https://www.kickstarter.com/projects/1598272670/chip-the-wor... might be more suitable (smaller screen but easier to pocket and has physical keyboard) when they are available.
And of course the schools don't have to provide them, if they already expect the students to have a TI calculator how is requiring them to have a cheap tablet or similar any different?
The key problems with this idea as I see it:
* Getting the new app-and-devices idea accepted as a viable alternative (the current graphing calculators are pretty entrenched).
* Writing the app in the first place, and then maintaining it. I doubt there would be a commercial impetus for anyone to do it so it would need to be some form of F/OSS arrangement or funded from education budgets. Maybe if I win the lottery and need a project to fill my spare time with I'll give it a go...