Students complete the WarmUp assignments before they receive any formal instruction on a particular topic. They earn credit for answering a question, substantiated by prior knowledge and whatever they managed to glean from the textbook. The answers do not have to be complete, or even correct. In fact, partially correct responses are particularly useful as classroom discussion fodder. In contrast to WarmUps, Puzzle exercises are assigned to students after they have received formal instruction on a particular topic. The Puzzles serve as the framework for a wrap-up session on a particular topic.