Mastery Challenges are done to level up user's skills. User get 50 energy points per problem users answer correctly in a Mastery Challenge. If users answer a problem wrong in a mastery challenge, users may level down in the skill. Users get a mastery challenge every 16 hours, but they won't if user doesn't have practiced skills available. User can also get the Geek of the week: mastery badge by completing 5 mastery challenges in a week and Geek of the week: practice by completing 5 practice tasks in a week.
Booster Challenges allows user to practice skills quickly without any penalty for getting the questions incorrect. After completing the Booster Challenge it goes back to regular mastery challenges.
A Mission Warm-Up is only available when user starts a Mission and can only be done once per Mission. They are meant to test their skills before user start a Mission, so there is usually not a penalty for getting the questions wrong, so user will only level down only if they had practiced that skill in the past. When they are done it shows what skills they probably have mastered. Then user can level up in those skills.
Mission Completion Screen
This screen appears when user complete a mission: