Texas Instruments TI-83 Plus Manual Book page 12

Scoring
After ten problems, a score is displayed along with a
congratulatory message based on the score.
If you press \  to leave the activity before you have
completed ten problems, the score you have achieved up to that
point is displayed.
The score is tallied in the following way:
•
Guessing correctly on the first try: 10 points.
•
Guessing correctly on the second try: 5 points.
•
Incorrect answer: 0 points.
After the score is displayed, press any key to return to the main
menu.
TI-83 Plus What Is My Angle? Application Page 12