Spaced repetition is the principle that you remember things best when you review them right before you'd forget them. Paper schedules every flashcard review for you using this principle (the FSRS algorithm).
How the schedule works
Each card has an internal interval and difficulty that grow when you remember it and shrink when you forget. After flipping a card, you grade your recall:
- Again - back to the start; the card returns within minutes
- Hard - interval grows slowly
- Good - interval grows on a steady curve
- Easy - interval grows quickly; you'll see this card less often
You can also use the keyboard: 1 = Again, 2 = Hard, 3 = Good, 4 = Easy.
A card you've answered "Good" a few times in a row might not return for weeks. A card you keep getting wrong returns daily until it sticks.
Reviewing a deck
Every flashcards page has its own deck. To review one:
- Open the page (or the page's flashcards tab in the AI features panel).
- Click Review in the deck header. The button shows the number of reviewable cards.
- Work through the queue. Switch between Learn mode (focus on cards that need work) and Standard mode (walk the whole deck in order) using the toggle in the header.
The session ends automatically when every card has reached the "Solid" bucket. The four buckets - New, Learning, Almost, Solid - tell you how each card is tracking this session.
Mastery tracking
Paper tracks how confidently you've answered each concept across reviews. The mastery signal feeds into adaptive quizzes - favouring topics you struggle with.
You don't have to do anything to enable this - it's based on your normal review activity.
Daily goal
The deck view shows your daily review goal and how many reviews you've completed today. Adjust the goal from the same control if 50 a day is too few or too many.
Tips
- 10–20 minutes a day works better than two-hour weekend marathons.
- Be honest with the Again button. Marking a card "Good" when you only half-remembered it pushes it back into the schedule prematurely.
- If a card is permanently confusing, edit it (the pencil icon during review) rather than re-failing it. A clearer prompt is the fastest fix.