Most courses grade by weighted categories — homework 30 percent, midterm 30 percent, final 40 percent — which means not all points are created equal. A point earned in a 40-percent category moves your grade more than twice as much as a point in a 15-percent category. The contribution of any category is simply your score in it multiplied by its weight: 80 percent on homework worth 30 percent contributes 80 x 0.30 = 24 points toward the final grade. Your course grade is the sum of these contributions, and the weights always sum to 100 percent (if they do not, something is off in the syllabus — or in your reading of it).
Computing your current standing takes the same math with a twist: for completed categories, use actual scores; for remaining ones, plug in scenarios. This is how you discover leverage: if homework is 20 percent and you have 95 percent banked, its 19 locked-in points are nearly maxed — extra effort there buys almost nothing, while the 40-percent final you have not taken yet holds 40 undecided points. Rational students allocate effort where the undecided weight is, not where they feel most comfortable.
The strategic corollary: never sacrifice a heavy category to polish a light one. Skipping a 5-percent quiz to study for a 40-percent exam is usually correct; the reverse is almost never correct. And when a syllabus offers to drop the lowest quiz or replace a grade, recalculate — dropped scores change both your average and the effective weights, sometimes dramatically.