diff --git a/development/tools/lyx-build b/development/tools/lyx-build
index 87e7aa04d9..f38482bd21 100755
--- a/development/tools/lyx-build
+++ b/development/tools/lyx-build
@@ -29,6 +29,8 @@ if [ "$LASTNUM" = "1" ]; then
   NUMFIX="st";
 elif [ "$LASTNUM" = "2" ]; then
   NUMFIX="nd";
+elif [ "$LASTNUM" = "3" ]; then
+  NUMFIX="rd";
 fi
 NUM="$LASTNUM$NUMFIX";