I did all this programming first in QBASIC, than in PowerBASIC which gave me a nice speedup. Fun thing is, since I was quite young back than, I didn't knew how to define functions in BASIC which complicated my code quite a bit.
I showed this software (which I've called ADDIMATH) to my math teacher, and he loved it! He even bought one copy for 0.50 Deutsche Mark on a 1.44MB floppy. He proudly told parents and other teachers about my software and allowed me to use it for my homework as long as I wouldn't give the software to my classmates.
Math - WolframAlpha
History - Wikipedia
Science - Wikipedia
Language - Google Translate
etc.
Rather than creating an app that does your homework for you, I think it would be more useful if we created apps that determined whether or not you needed homework in the first place and gave you the right amount of homework based on how well you're doing.
As an example, you could look at the work that the Khan Academy is doing: http://www.khanacademy.org/about/blog/post/58354379257/intro...
Have you read Neal Stephenson's The Diamond Age? What do you think of it?