Every once in a while, I find something that is useful, no strings attached, and just works. Anki is such a tool. It can take a bit to learn, but they made an entire set of videos to cover that. So what does it do? Well, there was a study done a long time ago about how you forget and when you forget. From this, many systems of memory refreshing have been developed. Anki is one of these, and it is aimed at students in a major way. It supports mathematical calculations, foreign languages, and as many questions as you want to put in! It is also free, available for basically everything, and did I mention useful? Yes? Well, I am mentioning it again!