Fixing division

scss/_core.scss

@@ -17,7 +17,7 @@
 /* makes the font 33% larger relative to the icon container */
 .icon-large:before {
   vertical-align: -10%;
-  font-size: 4/3em;
+  font-size: (4em/3);
 }
 
 /* makes sure icons active on rollover in links */
@@ -33,11 +33,11 @@ a {
 [class*=" icon-"] {
   &.icon-fixed-width {
     display: inline-block;
-    width: 16/14em;
+    width: (16em/14);
     text-align: right;
-    padding-right: 4/14em;
+    padding-right: (4em/14);
     &.icon-large {
-      width: 20/14em;
+      width: (20em/14);
     }
   }
 }

scss/_mixins.scss

@@ -42,7 +42,7 @@
     }
     .icon-stack-base {
       font-size: $base-font-size;
-      *line-height: $height / $base-font-size;
+      *line-height: #{$height / $base-font-size}em;
     }
   }
 }

scss/_variables.scss

@@ -6,7 +6,7 @@ $borderColor: #eeeeee !default;
 $iconMuted: #eeeeee !default;
 $iconLight: white !default;
 $iconDark: #333333 !default;
-$icons-li-width: 30em/14;
+$icons-li-width: (30em/14);
 
 
 $glass: "\f000";

scss/font-awesome-ie7.scss

@@ -26,7 +26,7 @@
 @import "variables";
 
 .icon-large {
-  font-size: 4/3em;
+  font-size: (4em/3);
   margin-top: -4px;
   padding-top: 3px;
   margin-bottom: -4px;