<p>@Legacy If you want a good grade, you need to use a calculator when its allowed
@4kidsdad the Ti-89 IS allowed on the AP Exams, as well as the SAT. It is not allowed on the ACT</p>
<p>the 84 should be enough, if you can buy the 89 its certainly more powerful, but its harder to get used to. It took me ages to discover some of the features that it has, and it can sometimes be hard to “translate” from ti84 to ti89 procedures. Menus are completely different and the calculator is very different.</p>