We need to find the mean of a set of five values.
In order to do so, we need to add all the values, and then divide the result by the total number of values.
So, adding those values, we obtain:
Notice that since they are all negative values, the result is the sum of their absolute values with the minus sign.
Now, since the total number of values in the given set is 5, we need to divide the previous result by 5. We obtain: