5 Steps to a 5: AP U.S. History Flashcards features 600 key terms that expert author Stephen Armstrong has selected as ones that frequently appear on AP U.S. History exams. This extra tool increases your knowledge and helps you achieve up to a maximum 5 score. You now have an additional way to master the key terms that are the basis of AP U.S. History success, delivered in a format that is convenient for your lifestyle.