Solution 34794: Inputting Absolute Values on the TI-83 Plus and TI-84 Plus Family of Graphing Calculators.
How do I input absolute values on the TI-83 Plus and TI-84 Plus family of graphing calculators?
The instructions below demonstrate how to input the abs( or absolute value function on the TI-83 Plus and TI-84 Plus family of graphing calculators.
Example: Find |-3|
• Press [MATH]
• Scroll right to highlight NUM and select 1:abs(
• Input -3. To make a value negative, use the negative or [(-)] key located below the  key.
• Press [ENTER] and the solution below should be displayed.
Please note that if you have "CLASSIC" selected as your display mode and not "MATHPRINT", you'll see an abs( function show up on your display instead of an actual absolute value box.
Please see the TI-83 Plus and TI-84 Plus Family guidebooks for additional information.