Now it is sounding to me as if it is possible that your students are at the 'i understrand it when you say it, but not well enough to do it myself' stage. Which means they need more homework. Basic drilling stuff. One odd thing I found was that students are really unhappy with * as multiply and ** as exponentation -- those that even knew what exponentation was. I thought 5 exercises using the notation would be enough. Wasn't. 10 was, though. Laura