Usefull apps for ISDR

One of the most usefull apps that are on the appstore is myscript calculator, is an app where you can write ecuations with your hand and the app understand the numbers you write, it also solves the ecuations telling you which is the missing data and you can have an idea of how to get that data in your notebook.
Another usefull app is ibooks because you can download pdf books from the internet and have them in your ipad for free, so yo can have books at any time without carryng a heavy backpack.
Clear vision is a shooter app which uses physics so you can learn how to kill a person from a long distance with calculations using the distance and the wind.
There are another apps that are usefull but they cost money like wolfran alpha which help you how to graph ecuations, others teach you programming language like python, C or Arduino, you can use this apps for free on a computer and hey are easier to use on it, computer have a lot of advantages over movile devices, in programming languages you can send your code to a micro controller from your computer.