With the right software, the TI-89 is a very powerful math tool

Of course, once you have mastered the math with your own brain, the calculator should be an indispensible tool

My high school normally gives out 85's for students to use during the year, but I found that the Table function makes the 86 a much more valuable tool than the 85.

This calculator is generally used in the engineering field, and the learning curve is slightly steeper than the recommended TI83, but I personally prefer this tool in my studies.