Por si algún profe quiere investigar sobre estas 70 apps y ver si le son de utlidad. Yo uso algunas // The 70 Best Apps For Teachers And Students - Edudemic. These are listed as itunes apps, but I'm sure a lot of them can be found for Android as well.
The internet's biggest and most complete list of free software for all students. Whether you are in the arts & humanities, liberal arts & sciences, engineering, architecture or any other major you should find it useful for your studies and for your budget