Step-by-step explanation:
Please see the attached picture and I hope I have given the right answer.
It's a glitch I believe (screenshot and contact your teacher)
Lets say your numbers are these...
10,20,30,40,50,60,70,80,90 and 100
you would add those to get 650
Now how many numbers did you add?
You added 10
so now divided
650 by 10
you get 65
that is the mean of those numbers!