Do you mean, -6 - 4 - -6 - 0 - 6 - 4 - -5 - 5 - -4 - -1 - 6 - -4?
If so, here's my working out:
-6 - 4 = -10
-10 - -6 = -4
-4 - 0 = -4
-4 - 6 = -10
-10 - 4 = -14
-14 - -5 = -9
-9 - 5 = -14
-14 - -4 = -10
-10 - -1 = -9
-9 - 6 = -15
-15 - -4 = -11
The answer is -11.
Hope this helps!