A question related to this one, on an equivalent problem on a community-college College Algebra exam. In the prior question most readers observed the error as a critical conceptual issue. Now consider this example of student work:
In this case, the distribution has been done correctly, and two of the three combinations of like terms. But in the very last term, a signed-arithmetic error has been made; the student replaced $-3-14$ with an incorrect $-11$.
On a percentage basis, what is the most appropriate amount of credit to award in a case like this? Assume that the problem is worth an appropriately granular number of points (not necessarily 10).