In a one-year functions and calculus course using a common textbook, three classes of Grade 10 students worked with graphics calculators throughout, five classes worked with graphics calculators for about two months, and four classes did not use graphics calculators. Posttest results showed that the students who had worked with graphics calculators tended to attempt more problems and obtain higher test scores than the students who had not used graphics calculators. Further analysis showed that the higher percentage of correct answers in the calculator classes appeared to be a result of students using graphical strategies more frequently and was largely restricted to below-average students. Use of