kinda hilarious watching this topic - the current kids are, it seems, children of grade inflation, and are entirely floored by the idea of "grading on a curve", with a certain percent of the class failing because they did least well https://twitter.com/alexhern/status/1294200553661227008 …
I clicked through, read a bunch, and was still unclear but all results for bell curves, and to "grade on a curve" means to assign letter grades based on that curve, once revealed