I personally think that in most cases TI-83 will do just fine, although I do see a lot of TI-89's. One warning though do not work all of your homework problems on the calculator, because I can't imagine any teacher with any kind of sense would allow a TI-89 calculator on a test. Afterall, it could do all the work for you. My professors now say that they recommend TI-30's or a similar scientific calculator. Furthermore, my math professors generally don't allow calculators. So my advice is this (especially in math class), get used to figuring it out with paper and pencil and forget the calculator. --- Learning without thought is labor lost; thought without learning is perilous. -- Confucius