Texas Instruments TI-83 PLUS - Manual (Page 603)

TI-83 Plus Memory and Variable Management 600
4. Press } and † to move the selection cursor ( 4 ) next to the item you
want to delete, and then press { . The variable is deleted from
memory. You can delete individual variables one by one from this
screen.
Note: If you are deleting programs or Apps, you will receive a message
asking you to confirm this delete action. Select
2:Yes to continue.
To leave any variable screen without deleting anything, press
y 5 , which displays the home screen.
Note: You cannot delete some system variables, such as the last-answer
variable
Ans and the statistical variable RegEQ .