I use these quizzes with the first grade Everyday Math curriculum unit on addition. Once a week, students take a different form of the quiz, timed for 5-10 minutes. Students who score a certain number correct each week get their name added to the "I have Fact Power!" poster in our classroom and are exempt from the following weeks' quizzes (many students opt to continue taking them). These weekly quizzes really motivate students to memorize and have quick recall of those pesky addition facts that