Ask HN: What are the best in-classroom education apps for K-5

I just got back from the first PTA meeting at my son's elementary school and we have a $200K surplus from last year. We need a solid technology plan to help spend this money effectively. I am thinking something related to tablets would likely offer the most bang per dollar, but don't have a good sense of what is out there specifically for the classroom. One limitation we have is we need flash support. Awesome apps the school already uses such as Dreambox use flash, so the ipad is likely not an option. I definitely like Class Dojo and plan to use that as one use case where a tablet in each classroom would make sense. I am hoping to help create a technology plan that maximizes value per dollar spent. We have a nice big surplus for a public school, but parents need to see it spent prudently if we expect them to be generous with their donations again this year. Do you have any recommendations? Do you have kids in a school that uses tablets in the classroom? Or know of good applications that make the teachers day easier given they have a tablet?

I have a Kindergartner and 2nd grader so am personally more biased towards those grades at the moment. Especially if we go with some kind of initial staged roll out.

Thanks for the advice.

-Wojtek