This is a tutorial that walks through some of the basic features of a TI83 or TI84 calculator. Here are the topics and where you can find them on the video timeline in case you want to fast forward:
00:15 General Math
03:44 Probability Functions
06:19 Trigonometry Functions
09:06 Graphing
17:04 Statistics
27:27 Programming
29:50 Using the "FINANCE" button