Look for error messages on the screen. Error messages are displayed as menu titles, like "ERR:," followed by the error syntax. Write down the error syntax.
Press "Quit" or "Clear" and the home screen will be displayed, or press "Goto" and the cursor will be displayed at the error location in the previous screen.
Correct the error by referring to Appendix B in the TI-83 "Guide Book," which is available from the Texas Instruments website (education.ti.com).
Refer to the "Error Type" column and identify the "Possible Causes and Suggested Remedies." For example, if the calculator returns an error message that says "ERR:DIM MISMATCH," you will know that you have tried to perform a calculation that references more than one list or matrix and that the dimensions don't match.
Perform the calculation again, making sure that you don't repeat the step or key stroke that caused the error.