diff --git a/less/mixins.less b/less/mixins.less
index de054784d8..f33b1ec6bc 100644
--- a/less/mixins.less
+++ b/less/mixins.less
@@ -414,7 +414,7 @@
   @media (min-width: @grid-float-breakpoint) {
     float: left;
     // Calculate width based on number of columns available
-    width: percentage(@columns / @grid-columns);
+    width: percentage((@columns / @grid-columns));
   }
   // Prevent columns from collapsing when empty
   min-height: 1px;
diff --git a/less/panels.less b/less/panels.less
index fe13a278fa..0d5a07ad40 100644
--- a/less/panels.less
+++ b/less/panels.less
@@ -17,7 +17,7 @@
 .panel-heading {
   margin: -15px -15px 15px;
   padding: 10px 15px;
-  font-size: @font-size-base * 1.25;
+  font-size: (@font-size-base * 1.25);
   font-weight: 500;
   background-color: @panel-heading-bg;
   border-bottom: 1px solid @panel-border;