Most high-school grading rewards two things at once: how much you understand, and how well you kept up with a calendar. Mastery-based learning separates them. A mastery check exists to answer one question — do you actually understand this unit yet? — and nothing about a bell or a due date is allowed to fake the answer.
The loop
You work through a unit at your own pace, then take a mastery check. Clear it at 85% or better and you move on. Fall short and you don't get a red mark and a shrug — you get a breakdown of exactly which ideas slipped, a short set of targeted practice for those specific gaps, and a retake when you're ready.
The goal isn't the grade on the first try. It's the gap, closed, before it becomes the thing that wrecks you two units later.
Why the retake isn't a punishment
In a traditional class, a 72% on Tuesday's test is permanent, and Wednesday's lesson assumes you got the 28% you missed. That's how students quietly accumulate holes until the whole subject feels impossible. Here, the retake is the point — most students clear a check on the second pass, and they move forward standing on solid ground instead of a guess.
It does mean you can't coast on partial credit. But it also means that when your transcript says you finished AP Calculus, you finished AP Calculus — not 78% of it.