Hey gang! It's the middle of February, and if you're in college, you probably have an exam coming up soon. I don't know how it is in every university, but pretty much all of my science related courses were 3 exams + 1 final (that would replace your lowest exam score). Sometimes I had a class where 10-20% of my grade came from other things, like research papers or group projects. But overall, my grade depended on those exams and I didn't have any buffer room for error.
I actually didn't have a smartphone until I graduated (it was a present to myself for surviving!) but I did have a Nexus 7 Tablet that was so valuable to me - I could pull up textbook pdfs and homework assignments, get on Blackboard and use apps! Since new apps are popping up all the time, here are some of the best apps to aid you with your studies - oh, and they're ALL FREE!