When you configure a study session you may have options to customize the learning sequence, also known as the "goal."
Mastery = Reach the green "mastered" status on the number of items you've selected. This uses Memorang's proprietary "short-term" spaced repetition algorithm which is optimized for knowledge acquisition. As you study, you should notice that certain facts may repeat until you can answer them correctly and demonstrate mastery. (Note: the "long-term" spaced repetition algorithm is optimized for knowledge retention). For example, if you select "10 facts" and a goal of "mastery" then once 10 previously non-mastered facts have been mastered, the study session will finish.
Ordered = Study facts sequentially in the original order defined by the author.
Shuffled = Study facts sequentially in a randomized order.