Is is okay to reuse content to create apps/games-for-practice?

Well I recommend you being original to be honest. Uploading content that is on YouTube or on the Internet in general a thousand times (and well explained) is not going to make you succeed in my opinion. Or yes, who knows. I suggest you filling the gaps or videos you didn't liked about KA and doing it yourself. Or getting some ideas from this website like badges, forums, streaks, etc. If you are referring to explicitly take the videos of KA and put it in a cost-website that is obviously illegal. If you think of doing literally the same exercises and then uploading it on your website I think you are wasting your time. 

The conclusion is that if you are going to make a similar content to KA, why don't you recommend KA? 

I think my question is being misunderstood here. I am not asking about copying the content - which is obviously illegal and unethical. Rather just aggregating and linking back to the original content either on KA or other sources from the app(games/exercises). Whereas these games are and will be my own creation.

Thank you for your time. I believe it would be best to re-ask this question if and when the app is on the stores for a demo.

Hi anupshinde,

I would highly suggest contacting support@khanacademy.org.  They will direct your question to whoever needs to answer it.