diff --git a/extensions/TeX/cancel.js b/extensions/TeX/cancel.js
new file mode 100644
index 000000000..2b23de23f
--- /dev/null
+++ b/extensions/TeX/cancel.js
@@ -0,0 +1,16 @@
+/*
+ *  /MathJax/extensions/TeX/cancel.js
+ *  
+ *  Copyright (c) 2010 Design Science, Inc.
+ *
+ *  Part of the MathJax library.
+ *  See http://www.mathjax.org for details.
+ * 
+ *  Licensed under the Apache License, Version 2.0;
+ *  you may not use this file except in compliance with the License.
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ */
+
+MathJax.Extension["TeX/cancel"]={version:"1.1",ALLOWED:{arrow:1,color:1,mathcolor:1,background:1,mathbackground:1,padding:1,thickness:1}};MathJax.Hub.Register.StartupHook("TeX Jax Ready",function(){var d=MathJax.InputJax.TeX,c=d.Definitions.macros,a=MathJax.ElementJax.mml,b=MathJax.Extension["TeX/cancel"];b.setAttributes=function(j,f){if(f!==""){f=f.replace(/ /g,"").split(/,/);for(var h=0,e=f.length;h<e;h++){var g=f[h].split(/[:=]/);if(b.ALLOWED[g[0]]){if(g[1]==="true"){g[1]=true}if(g[1]==="false"){g[1]=false}j[g[0]]=g[1]}}}return j};c.cancel=["Cancel",a.NOTATION.UPDIAGONALSTRIKE];c.bcancel=["Cancel",a.NOTATION.DOWNDIAGONALSTRIKE];c.xcancel=["Cancel",a.NOTATION.UPDIAGONALSTRIKE+" "+a.NOTATION.DOWNDIAGONALSTRIKE];c.cancelto="CancelTo";d.Parse.Augment({Cancel:function(f,h){var e=this.GetBrackets(f),g=this.ParseArg(f);var i=b.setAttributes({notation:h},e);this.Push(a.menclose(g).With(i))},CancelTo:function(f,h){var j=this.ParseArg(f),e=this.GetBrackets(f),g=this.ParseArg(f);var i=b.setAttributes({notation:a.NOTATION.UPDIAGONALSTRIKE,arrow:true},e);j=a.mpadded(j).With({depth:"-.1em",height:"+.1em",voffset:".1em"});this.Push(a.msup(a.menclose(g).With(i),j))}});MathJax.Hub.Startup.signal.Post("TeX cancel Ready")});MathJax.Ajax.loadComplete("[MathJax]/extensions/TeX/cancel.js");
+
diff --git a/unpacked/extensions/TeX/cancel.js b/unpacked/extensions/TeX/cancel.js
new file mode 100644
index 000000000..51db5c961
--- /dev/null
+++ b/unpacked/extensions/TeX/cancel.js
@@ -0,0 +1,105 @@
+/*************************************************************
+ *
+ *  MathJax/extensions/TeX/cancel.js
+ *  
+ *  Implements the \cancel, \bcancel, \xcancel, and \cancelto macros.
+ *  
+ *  Usage:
+ *  
+ *      \cancel{math}            % strikeout math from lower left to upper right
+ *      \bcancel{math}           % strikeout from upper left to lower right
+ *      \xcancel{math}           % strikout with an X
+ *      \cancelto{value}{math}   % strikeout with arrow going to value
+ *  
+ *  ---------------------------------------------------------------------
+ *  
+ *  Copyright (c) 2011 Design Science, Inc.
+ * 
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+MathJax.Extension["TeX/cancel"] = {
+  version: "1.1",
+
+  //
+  //  The attributes allowed in \enclose{notation}[attributes]{math}
+  //
+  ALLOWED: {
+    arrow: 1,
+    color: 1, mathcolor: 1,
+    background: 1, mathbackground: 1,
+    padding: 1,
+    thickness: 1
+  }
+};
+
+MathJax.Hub.Register.StartupHook("TeX Jax Ready",function () {
+  var TEX = MathJax.InputJax.TeX,
+      MACROS = TEX.Definitions.macros,
+      MML = MathJax.ElementJax.mml,
+      CANCEL = MathJax.Extension["TeX/cancel"];
+      
+      CANCEL.setAttributes = function (def,attr) {
+        if (attr !== "") {
+          attr = attr.replace(/ /g,"").split(/,/);
+          for (var i = 0, m = attr.length; i < m; i++) {
+            var keyvalue = attr[i].split(/[:=]/);
+            if (CANCEL.ALLOWED[keyvalue[0]]) {
+              if (keyvalue[1] === "true") {keyvalue[1] = true}
+              if (keyvalue[1] === "false") {keyvalue[1] = false}
+              def[keyvalue[0]] = keyvalue[1];
+            }
+          }
+        }
+        return def;
+      };
+  
+  //
+  //  Set up macro
+  //
+  MACROS.cancel  = ['Cancel',MML.NOTATION.UPDIAGONALSTRIKE];
+  MACROS.bcancel = ['Cancel',MML.NOTATION.DOWNDIAGONALSTRIKE];
+  MACROS.xcancel = ['Cancel',MML.NOTATION.UPDIAGONALSTRIKE+" "+MML.NOTATION.DOWNDIAGONALSTRIKE];
+  MACROS.cancelto = 'CancelTo';
+
+  TEX.Parse.Augment({
+    //
+    //  Implement \cancel[attributes]{math},
+    //            \bcancel[attributes]{math}, and
+    //            \xcancel[attributes]{math}
+    //
+    Cancel: function(name,notation) {
+      var attr = this.GetBrackets(name), math = this.ParseArg(name);
+      var def = CANCEL.setAttributes({notation: notation},attr);
+      this.Push(MML.menclose(math).With(def));
+    },
+    
+    //
+    //  Implement \cancelto{value}[attributes]{math}
+    //
+    CancelTo: function(name,notation) {
+      var value = this.ParseArg(name),
+          attr = this.GetBrackets(name),
+          math = this.ParseArg(name);
+      var def = CANCEL.setAttributes({notation: MML.NOTATION.UPDIAGONALSTRIKE, arrow:true},attr);
+      value = MML.mpadded(value).With({depth:"-.1em",height:"+.1em",voffset:".1em"});
+      this.Push(MML.msup(MML.menclose(math).With(def),value));
+    }
+
+  });
+
+  MathJax.Hub.Startup.signal.Post("TeX cancel Ready");
+  
+});
+
+MathJax.Ajax.loadComplete("[MathJax]/extensions/TeX/cancel.js");