diff --git a/lib/less/index.js b/lib/less/index.js
index ec2d302e3..009a37be2 100644
--- a/lib/less/index.js
+++ b/lib/less/index.js
@@ -88,7 +88,7 @@ var less = {
  'call',       'url',        'alpha',      'import',
  'mixin',      'comment',    'anonymous',  'value',
  'javascript', 'assignment', 'condition',  'paren',
- 'media', 'ratio'
+ 'media'
 ].forEach(function (n) {
     require('./tree/' + n);
 });
diff --git a/lib/less/parser.js b/lib/less/parser.js
index 2bc229c6d..c00ca727b 100644
--- a/lib/less/parser.js
+++ b/lib/less/parser.js
@@ -61,6 +61,7 @@ less.Parser = function Parser(env) {
         furthest,    // furthest index the parser has gone to
         chunks,      // chunkified input
         current,     // index of current chunk, in `input`
+        parens = 0,  // current depth of nested parentheses
         parser;
 
     var that = this;
@@ -397,6 +398,7 @@ less.Parser = function Parser(env) {
                         else                                  throw new(LessError)(importError, env);
                     }
 
+                    css = css.replace(/\s+(\/)\s+/g, "$1");
                     if (options.yuicompress && less.mode === 'node') {
                         return require('./cssmin').compressor.cssmin(css);
                     } else if (options.compress) {
@@ -577,7 +579,7 @@ less.Parser = function Parser(env) {
                     nameLC = name.toLowerCase();
 
                     if (nameLC === 'url') { return null }
-                    else                { i += name.length }
+                    else                  { i += name.length }
 
                     if (nameLC === 'alpha') {
                         alpha_ret = $(this.alpha);
@@ -587,10 +589,15 @@ less.Parser = function Parser(env) {
                     }
 
                     $('('); // Parse the '(' and consume whitespace.
+                    parens++;
 
                     args = $(this.entities.arguments);
 
-                    if (! $(')')) return;
+                    if (! $(')')) {
+                        parens--;
+                        return;
+                    }
+                    parens--;
 
                     if (name) { return new(tree.Call)(name, args, index, env.filename) }
                 },
@@ -604,8 +611,7 @@ less.Parser = function Parser(env) {
                     return args;
                 },
                 literal: function () {
-                    return $(this.entities.ratio) ||
-                           $(this.entities.dimension) ||
+                    return $(this.entities.dimension) ||
                            $(this.entities.color) ||
                            $(this.entities.quoted);
                 },
@@ -702,20 +708,6 @@ less.Parser = function Parser(env) {
                     }
                 },
 
-                //
-                // A Ratio
-                //
-                //    16/9
-                //
-                ratio: function () {
-                  var value, c = input.charCodeAt(i);
-                  if (c > 57 || c < 48) return;
-
-                  if (value = $(/^(\d+\/\d+)/)) {
-                    return new(tree.Ratio)(value[1]);
-                  }
-                },
-
                 //
                 // JavaScript code to be evaluated
                 //
@@ -746,27 +738,6 @@ less.Parser = function Parser(env) {
                 if (input.charAt(i) === '@' && (name = $(/^(@[\w-]+)\s*:/))) { return name[1] }
             },
 
-            //
-            // A font size/line-height shorthand
-            //
-            //     small/12px
-            //
-            // We need to peek first, or we'll match on keywords and dimensions
-            //
-            shorthand: function () {
-                var a, b;
-
-                if (! peek(/^[@\w.%-]+\/[@\w.-]+/)) return;
-
-                save();
-
-                if ((a = $(this.entity)) && $('/') && (b = $(this.entity))) {
-                    return new(tree.Shorthand)(a, b);
-                }
-
-                restore();
-            },
-
             //
             // Mixins
             //
@@ -786,7 +757,7 @@ less.Parser = function Parser(env) {
                     var elements = [], e, c, args = [], arg, index = i, s = input.charAt(i), name, value, important = false;
 
                     if (s !== '.' && s !== '#') { return }
-                    
+
                     save(); // stop us absorbing part of an invalid selector
 
                     while (e = $(/^[#.](?:[\w-]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+/)) {
@@ -826,7 +797,7 @@ less.Parser = function Parser(env) {
                     if (elements.length > 0 && ($(';') || peek('}'))) {
                         return new(tree.mixin.Call)(elements, args, index, env.filename, important);
                     }
-                    
+
                     restore();
                 },
 
@@ -885,7 +856,7 @@ less.Parser = function Parser(env) {
                             }
                         } while ($(','))
 
-                        // .mixincall("@{a}"); 
+                        // .mixincall("@{a}");
                         // looks a bit like a mixin definition.. so we have to be nice and restore
                         if (!$(')')) {
                             furthest = i;
@@ -1014,7 +985,7 @@ less.Parser = function Parser(env) {
                     //   :nth-child(@a)
                     // vs
                     //   .a:hover(@a)
-                
+
                     e = $('&');
                     $('(');
                     if (e) {
@@ -1098,8 +1069,6 @@ less.Parser = function Parser(env) {
                     if ((name.charAt(0) != '@') && (match = /^([^@+\/'"*`(;{}-]*);/.exec(chunks[j]))) {
                         i += match[0].length - 1;
                         value = new(tree.Anonymous)(match[1]);
-                    } else if (name === "font") {
-                        value = $(this.font);
                     } else {
                         value = $(this.value);
                     }
@@ -1126,9 +1095,9 @@ less.Parser = function Parser(env) {
             //
             "import": function () {
                 var path, features, index = i;
-                
+
                 save();
-                
+
                 var dir = $(/^@import(?:-(once))?\s+/);
 
                 if (dir && (path = $(this.entities.quoted) || $(this.entities.url))) {
@@ -1137,7 +1106,7 @@ less.Parser = function Parser(env) {
                         return new(tree.Import)(path, imports, features, (dir[1] === 'once'), index);
                     }
                 }
-                
+
                 restore();
             },
 
@@ -1149,7 +1118,7 @@ less.Parser = function Parser(env) {
                         nodes.push(e);
                     } else if ($('(')) {
                         p = $(this.property);
-                        e = $(this.entity);
+                        e = $(this.value);
                         if ($(')')) {
                             if (p && e) {
                                 nodes.push(new(tree.Paren)(new(tree.Rule)(p, e, null, i, true)));
@@ -1209,7 +1178,7 @@ less.Parser = function Parser(env) {
                 if (value = $(this['import']) || $(this.media)) {
                     return value;
                 }
-                
+
                 save();
 
                 name = $(/^@[a-z-]+/);
@@ -1265,24 +1234,8 @@ less.Parser = function Parser(env) {
                         return new(tree.Directive)(name, value);
                     }
                 }
-                
-                restore();
-            },
-            font: function () {
-                var value = [], expression = [], weight, shorthand, font, e;
-
-                while (e = $(this.shorthand) || $(this.entity)) {
-                    expression.push(e);
-                }
-                value.push(new(tree.Expression)(expression));
 
-                if ($(',')) {
-                    while (e = $(this.expression)) {
-                        value.push(e);
-                        if (! $(',')) { break }
-                    }
-                }
-                return new(tree.Value)(value);
+                restore();
             },
 
             //
@@ -1313,15 +1266,28 @@ less.Parser = function Parser(env) {
             sub: function () {
                 var e;
 
-                if ($('(') && (e = $(this.expression)) && $(')')) {
-                    return e;
+                if ($('(')) {
+                    parens++;
+                    if (e = $(this.expression)) {
+                        expect(')');
+                        parens--;
+                        return e;
+                    }
                 }
             },
             multiplication: function () {
-                var m, a, op, operation;
+                var m, a, op, operation, expression = [];
                 if (m = $(this.operand)) {
-                    while (!peek(/^\/\*/) && (op = ($('/') || $('*'))) && (a = $(this.operand))) {
-                        operation = new(tree.Operation)(op, [operation || m, a]);
+                    while (!peek(/^\/\*/) && (op = ($('/') || $('*')))) {
+                        if (op === '/' && !parens) {
+                            expression.push(operation || m);
+                            expression.push(new(tree.Anonymous)('/'));
+                            operation = new(tree.Expression)(expression);
+                        } else if (a = $(this.operand)) {
+                            operation = new(tree.Operation)(op, [operation || m, a]);
+                        } else {
+                            break;
+                        }
                     }
                     return operation || m;
                 }
@@ -1393,6 +1359,9 @@ less.Parser = function Parser(env) {
 
                 while (e = $(this.addition) || $(this.entity)) {
                     entities.push(e);
+                    if (!peek(/^\/\*/) && (delim = $('/'))) {
+                        entities.push(new(tree.Anonymous)(delim));
+                    }
                 }
                 if (entities.length > 0) {
                     return new(tree.Expression)(entities);
diff --git a/lib/less/tree/ratio.js b/lib/less/tree/ratio.js
deleted file mode 100644
index f7622fb89..000000000
--- a/lib/less/tree/ratio.js
+++ /dev/null
@@ -1,13 +0,0 @@
-(function (tree) {
-
-tree.Ratio = function (value) {
-    this.value = value;
-};
-tree.Ratio.prototype = {
-    toCSS: function (env) {
-        return this.value;
-    },
-    eval: function () { return this }
-};
-
-})(require('../tree'));
diff --git a/test/css/css.css b/test/css/css.css
index 78ea14dc7..4f06f4301 100644
--- a/test/css/css.css
+++ b/test/css/css.css
@@ -62,6 +62,9 @@ p + h1 {
   padding: 1px 0 2px 0;
   font: normal small/20px 'Trebuchet MS', Verdana, sans-serif;
   font: 0/0 a;
+  border-radius: 5px/10px;
+  background: url("img.jpg") center/100px;
+  background: #ffffff url(image.png) center/1px 100px repeat-x scroll content-box padding-box;
 }
 .misc {
   -moz-border-radius: 2px;
diff --git a/test/css/mixins-args.css b/test/css/mixins-args.css
index d5b67f304..feba5c2e9 100644
--- a/test/css/mixins-args.css
+++ b/test/css/mixins-args.css
@@ -72,3 +72,8 @@ body {
   border: "{";
   width: "{";
 }
+.slash-vs-math {
+  border-radius: 2px/5px;
+  border-radius: 5px/10px;
+  border-radius: 6px;
+}
diff --git a/test/css/parens.css b/test/css/parens.css
index 36487fe59..71d3d0d5c 100644
--- a/test/css/parens.css
+++ b/test/css/parens.css
@@ -9,6 +9,7 @@
   width: 96;
   height: 113;
   margin: 12;
+  border-radius: 8px/7px;
 }
 .nested-parens {
   width: 71;
diff --git a/test/less/css.less b/test/less/css.less
index abcd2c08d..3d2017891 100644
--- a/test/less/css.less
+++ b/test/less/css.less
@@ -67,8 +67,11 @@ p + h1 {
 #more-shorthands {
   margin: 0;
   padding: 1px 0 2px 0;
-  font: normal small/20px 'Trebuchet MS', Verdana, sans-serif; 
+  font: normal small/20px 'Trebuchet MS', Verdana, sans-serif;
   font: 0/0 a;
+  border-radius: 5px / 10px;
+  background: url("img.jpg") center / 100px;
+  background: #fff url(image.png) center / 1px 100px repeat-x scroll content-box padding-box;
 }
 
 .misc {
diff --git a/test/less/media.less b/test/less/media.less
index 3dc1aabba..66f9fc447 100644
--- a/test/less/media.less
+++ b/test/less/media.less
@@ -20,7 +20,7 @@
     body { max-width: @base * 60; }
 }
 
-@media all and (device-aspect-ratio: 16/9) {
+@media all and (device-aspect-ratio: 16 / 9) {
    body { max-width: 800px; }
 }
 
@@ -172,7 +172,7 @@ body {
   }
 }
 
-@media (-webkit-min-device-pixel-ratio: 2), (min--moz-device-pixel-ratio: 2), (-o-min-device-pixel-ratio: 2/1), (min-resolution: 2dppx), (min-resolution: 128dpcm) {
+@media (-webkit-min-device-pixel-ratio: 2), (min--moz-device-pixel-ratio: 2), (-o-min-device-pixel-ratio: 2 / 1), (min-resolution: 2dppx), (min-resolution: 128dpcm) {
   .b {
     background: red;
   }
diff --git a/test/less/mixins-args.less b/test/less/mixins-args.less
index ea43a0a53..656ad023d 100644
--- a/test/less/mixins-args.less
+++ b/test/less/mixins-args.less
@@ -128,3 +128,13 @@ body {
 .edge-case {
     .mixin-arguments("{");
 }
+
+// Division vs. Literal Slash
+.border-radius(@r: 2px/5px) {
+  border-radius: @r;
+}
+.slash-vs-math {
+  .border-radius();
+  .border-radius(5px/10px);
+  .border-radius((3px * 2px));
+}
diff --git a/test/less/operations.less b/test/less/operations.less
index 46b0aa393..637d43e3c 100644
--- a/test/less/operations.less
+++ b/test/less/operations.less
@@ -1,13 +1,13 @@
 #operations {
   color: #110000 + #000011 + #001100; // #111111
-  height: 10px / 2px + 6px - 1px * 2; // 9px
+  height: (10px / 2px + 6px - 1px * 2); // 9px
   width: 2 * 4 - 5em; // 3em
   .spacing {
-    height: 10px / 2px+6px-1px*2;
+    height: (10px / 2px+6px-1px*2);
     width: 2  * 4-5em;
   }
   substraction: 20 - 10 - 5 - 5; // 0
-  division: 20 / 5 / 4; // 1
+  division: (20 / 5 / 4); // 1
 }
 
 @x: 4;
@@ -20,7 +20,7 @@
 }
 
 .with-functions {
-  color: rgb(200, 200, 200) / 2;
+  color: (rgb(200, 200, 200) / 2);
   color: 2 * hsl(0, 50%, 50%);
   color: rgb(10, 10, 10) + hsl(0, 50%, 50%);
 }
@@ -37,7 +37,7 @@
 }
 
 .rem-dimensions {
-  font-size: 20rem / 5 + 1.5rem; // 5.5rem
+  font-size: (20rem / 5 + 1.5rem); // 5.5rem
 }
 
 .colors {
@@ -46,7 +46,7 @@
   background-color: #222222 - #fff; // #000000
   .other {
     color: 2 * #111; // #222222
-    border-color: #333333 / 3 + #111; // #222222
+    border-color: (#333333 / 3 + #111); // #222222
   }
 }
 
diff --git a/test/less/parens.less b/test/less/parens.less
index e020c7eb3..51bd21f7b 100644
--- a/test/less/parens.less
+++ b/test/less/parens.less
@@ -11,7 +11,8 @@
   padding: (2 * @var) 4 4 (@var * 1px);
   width: (@var * @var) * 6;
   height: (7 * 7) + (8 * 8);
-  margin: 4 * (5 + 5) / 2 - (@var * 2);
+  margin: (4 * (5 + 5) / 2) - (@var * 2);
+  border-radius: 4px * (1 + 1) / @var + 3px;
   //margin: (6 * 6)px;
 }