# Train: mixed questions and spaced review

The «Train» mode gathers the questions of all a challenge's stages into one session. Every answer puts the question into the review schedule — a right one comes back later, a wrong one soon.

## Where to practice

* **Train** — on any challenge with questions: on the repository's **Learn** tab, on the challenge
  page and in the list on [Learn](https://skillok.org/learn). You do not need to complete stages for it. A session has
  up to 20 mixed questions: those due for review and up to 10 new ones. No more than 20 new ones a day
  across all challenges, so reviews do not pile up later.
* **Review** — a separate screen, [/learn/review](https://skillok.org/learn/review), the **Review** button on the
  [Learn](https://skillok.org/learn) page. It has the questions from all your challenges that are due today, up to 20 at a
  time. Review has no new questions.

Days are counted in the account's time zone — Moscow by default: «today» ends at midnight.

To practice you need to sign in and have access to the challenge's repository.

## Questions

The screen: the question in the middle, a progress bar at the top, the answer and an explanation at
the bottom. Keys work: digits pick an option or a card rating, Enter answers and moves on. The answer
sound is turned on and off with a button on the screen. Question kinds:

* single or multiple choice — part of the right ones gives «Partially correct»;
* order — arrange the steps: drag a row, or pick an item and its place;
* pairs — pick an item on the left, then its pair on the right;
* gaps in a text;
* a number with a tolerance;
* a short answer in a word;
* a card — recall the answer, press **Show the answer** and honestly rate yourself: **Forgot**,
  **Hard**, **Remembered** or **Easy**. A card has no right answer — the schedule follows your rating.

A wrongly answered question comes back at the end of the same session, up to twice. At the end —
«Right the first time: 7 of 10».

## The schedule

After an answer the question gets the date of its next showing — «Next showing in N days»:

* the first right answer — in a day, the second — in 6 days; after that the interval grows with every
  right answer, the faster the easier the question is for you;
* a mistake or «Forgot» brings the question back in a day and starts the count over.

This is the SM-2 algorithm. When the date comes, the question appears in «Review today» on the
[Learn](https://skillok.org/learn) page and in the feed. An answer before the due date is checked but does not move the
schedule.

Answers to stage questions while taking a challenge also put the questions into the schedule: what you
completed comes back as review by itself.

There is no model call here: checking an answer is instant and free.

## What is visible

A right answer in review is marked in the activity calendar on your profile. An answer before the due
date does not move the schedule. In detail — [Progress](https://skillok.org/docs/en/learning/progress-and-achievements).

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https://skillok.org/docs/en/learning/training