<p>First I would like to say that on any math test, you should probably use the calculator you are most comfortable with. </p>
<p>With that said, I agree with gcf. The most useful function is solve. However, when I took the Math 2C, I found that I really didn’t need my 89 except for three of four problems. It depends on how many little tricks and formulas you know to begin with.</p>