3x (6,7,8,9,12)

Popularity (by total correct streak): 2
Popularity (by number of users): 1

Cards

3x6 18  
3X7 21  
3x8 24  
3x9 27  
3x12 36  

Quisition is a browser-based flashcard system that repeats old cards and introduces new ones at optimal time intervals. You can create your own card packs or use those developed by others.