Hello!
This is just a project I did to improve my knowledge of Qt, and try a bit of QML. So it's neither really a breakthrough (there are dozen of calculators out there), nor really finished (though if people want, I'll work a bit more on it).
But anyway, it works, so I'll share the debs and the code!
Code is shared on BitBucket

N9 version (ovi store)

N900 version (extra testing)


I have attached some screen shots (I haven't made two qml versions, which in retrospect is bad, but because of that the app has the same ugly look on both devices) too.