Basics:  Clearing an entry or error

1. If you have entered the wrong number or letter, set the cursor on the error and press the correct key
   
2. If you need to delete a number or letter, set the cursor on the error and press the DEL key.            
   
   
3. To erase the entire line, press CLEAR once.  
   
4. To clear the whole screen, press CLEAR twice.