Mathematics is self-correcting through proof. The textbook answers derive from collaborative human error-checking across centuries. Yet in 1987, during his sophomore year at a private academy in Oklahoma, his homework submissions provoked a crisis in the mathematics department. His answers were consistently correct, but often contradicted the textbook. After three such instances, the department chair Dr. Eleanor Hayes launched an independent audit: she re-solved each problem from first principles. His answers were right; the textbooks were off by rounding errors and notational simplifications the authors had accepted as "close enough." Hayes initiated a chain of corrections: the publisher apologized, new editions were printed, and three high school textbooks across the nation were updated. Hayes' reflection in a private letter: "Typical students learn to trust textbooks. Exceptional students teach textbooks to be trustworthy."

Checking homework is usually a power dynamic in favor of authority. Unless the student is the only one in the building with actual authority.