fix: template fix for null_card
diff --git a/erpnext/www/lms/course.html b/erpnext/www/lms/course.html
index 250c39d..c86ac9c 100644
--- a/erpnext/www/lms/course.html
+++ b/erpnext/www/lms/course.html
@@ -96,7 +96,7 @@
 				{{ card(topic) }}
 			{% endfor %}
 			{% if topics %}
-				{% for n in range(((topics|length)%3)) %}
+				{% for n in range( (3 - (topics|length)) %3) %}
 					{{ null_card() }}
 				{% endfor %}
 			{% endif %}