That looks like a cool app, but it is not a new kind of calculator: see also Calca and Soulver for previous work in this space.

I think adding a grapher is a real advance, however.

I've always liked the idea of a more free form excel. Excel is great to dink around with estimations but it's way overkill for the job. Something like this looks perfect for those "back of the envelope" calculations that are more in tune with how we really think.

Looks inapired by Bret Victor - http://worrydream.com/#!/MediaForThinkingTheUnthinkable

Now this is an interesting app.

Anyone knows if there is something similar available for android?