Processing. The device interprets the input in some way.

Output. The results are displayed.

Storage. The results may be stored for later retrieval.

In the case of the TI-83, the cycle begins when you input a sequence of commands using the keypad. As you press keys the value of the key is shown on the display window. Processing begins when you press the ENTER key (the key in the lower right of the keypad). Pressing the ENTER key signals the calculator that the input sequence is complete and it is time to perform a calculation. After the calculator performs the requested calculation the results are displayed on the screen and stored in the calculator.

Initially, all the buttons and features of the TI–83 may seem intimidating, but once you learn some of the basic features you’ll find the calculator a powerful and easy to use tool. Don’t be afraid to experiment with your calculator. Aside from physical damage such as dropping it, or spilling coffee on it, the worst thing that can happen to your calculator is that you will lose information stored electronically and the calculator will be returned to its original (out-of-box) condition.

The manual that came with the TI–83 may seem even more intimidating than the calculator itself, but it’s got an index for looking things up, and an extremely useful summary of commands in appendix A. Also, the sections entitled Getting Started, and Chapter 1: Operating the TI–83, are quite useful. Don’t lose your manual (or throw it away), you’ll regret it later on. Knowledge is power, and there’s lots of it in that manual. You should also hold on to (and carry with you) the little black cord that came with your calculator. It is used to exchange information and programs between calculators. We’ll be doing a fair amount of this, so hang on to that little cord. 

The TI–83 Keypad and Notation

The figure to the right shows the TI–83 calculator.

At the top of the calculator is a 96x64 pixel liquid crystal display (LCD) where the calculator displays the results of calculations.

Just below the display are the four graphing keys. These keys are used to interact with the graphing and table features of the calculator. The graphing keys are blue with white lettering. Each key has at least two functions. The primary function of each key is shown in white on the key, the secondary is shown in yellow just above the key. To access the secondary function of a key you first press (and release) the yellow[2^nd] key near the top left side of the TI–83. To refer to keys on the calculator keypad we will enclose the key’s name in square braces using a bold font. For example: To turn the calculator on press the [ON] button in the lower left corner of the keypad. When instructions involve the secondary features of a key, we will indicate that you should first press the [2^nd] key, and then give the secondary (yellow) name of the key. Using this convention the instructions to turn the calculator off are: press [2nd][OFF].

Some keys have a third function listed in green accessed by pressing the green [ALPHA] key located directly under the [2nd] key. Like the [2nd] key, it is pressed and released, to access the action described by the green text above and to the right of keys. When inputting text you can avoid having to press the [ALPHA] key before each character by locking the calculator in the [ALPHA] mode. To do this you press [2nd][A-LOCK]. To switch back to normal mode just press the [ALPHA] key again.

You can determine which interpretation the calculator will assign to your next keystroke by looking at the shape of the flashing cursor. If the cursor is a blinking solid box the calculator will assign the primary (white) function to the key. If either the[2nd]or [ALPHA] key is active the cursor shape will change as shown below.