Even though you can only use Siri to input data into the app, it still does a great job. Once Siri gives you an output you can click it to open it in the viewer. After it opens it gives you some other choices and things like that. So for it being free I love it. If you want something more complex and where you dont have to use Siri to input data, go buy their full app, I did and have never regretted it. Another thing you could do is go to their website directly and then use it for free that way... If you dont want to pay for the full app on your mobile device. But still its under $3 and worth every penny!!