This is to help you learn to take advantage of the distributive property and the fact that multiplication can simplify repeated addition.
The numbers to be added include ...
3 values that are -7
4 values that are -8
3 values that are 11
This means we can add 11 and -7, and multiply the result by 3. It also means we can multiply -8 by 4. The sum of these products will be the same as the sum of the original 10-number set.