Final answer:
The sum of the lowest number (-9) and the highest number (6) in the given list is -3.
Step-by-step explanation:
To add together the lowest number and the highest number in the given list, we need to identify the lowest and highest numbers first.
The lowest number in the list is -9, while the highest number is 6.
Adding -9 and 6 gives us a sum of -3.
Learn more about Addition of numbers