Spaced Repetition System is a learning method based on reviewing material at optimal time intervals. The app uses answer evaluation (depending on the mode – either self-assessment or automatic grading) to decide when a particular word should appear again.
For example, if you answer incorrectly, the same word will show up again in a few minutes. If you know the word well, it will be shown again in a few days or weeks, and then increasingly less often.
Thanks to this, you learn efficiently and don’t waste time repeating things you already know.