diff --git a/papers/scp/PLFA.tex b/papers/scp/PLFA.tex
index dc66927c..bc7fd5d5 100755
--- a/papers/scp/PLFA.tex
+++ b/papers/scp/PLFA.tex
@@ -946,7 +946,7 @@ questions rather than two of three).
 % exam for the courses run at Edinburgh and PUC-Rio.  While scores vary
 % widely on the mock, all students achieve perfection on the
 For the courses run at Edinburgh and PUC-Rio, the scores vary
-widely on the mock: minimum <20%, maximum 100%, mean
+widely on the mock: minimum <20\%, maximum 100\%, mean
 77.8, standard deviation 27.6. But all students achieve perfection on the
 exam.  (The one exception was a PUC-Rio student who did not attend
 classes or sit the mock.)  Similar results were achieved at Edinburgh