diff --git a/Sinon.js.js b/Sinon.js.js
new file mode 100644
index 0000000..1b2c837
--- /dev/null
+++ b/Sinon.js.js
@@ -0,0 +1,25 @@
+ var test = require('unit.js');
+	
+	function once(fn) {
+  var returnValue;
+  var called = false;
+  return function() {
+    if (!called) {
+      called = true;
+      returnValue = fn.apply(this, arguments);
+    }
+    return returnValue;
+  };
+};
+var jQuery = {
+  ajax: function() {}
+};
+function getTodos(listId, callback) {
+  jQuery.ajax({
+    url: '/todo/' + listId + '/items',
+    success: function(data) {
+      // Node-style CPS: callback(err, data)
+      callback(null, data);
+    }
+  });
+}
\ No newline at end of file
diff --git a/calculator.js b/calculator.js
index caf34db..90e04d6 100644
--- a/calculator.js
+++ b/calculator.js
@@ -11,5 +11,16 @@ function substract(num1, num2){
   return num1 - num2;
 }
 
+function multiplicate(num1, num2){
+  return num1 * num2;
+}
+
+function divide(num1, num2){
+  return num1 / num2;
+}
+
 module.exports.add = add;
+module.exports.substract = substract;
+module.exports.multiplicate = multiplicate;
+module.exports.divide = divide;
 module.exports.isNumber = isNumber;
diff --git a/index.html b/index.html
index cc6a9d9..9a3a6f6 100644
--- a/index.html
+++ b/index.html
@@ -22,6 +22,8 @@ <h1>Silly Calculator</h1>
     <select id="operator" size="1">
       <option value="add">+</option>
       <option value="substract">-</option>
+	  <option value="multiplicate">*</option>
+      <option value="divide">/</option>
     </select>
     <input type="text" id="num2" value="1" />
     <div>=</div>
diff --git a/main.js b/main.js
index 957a234..f1e4457 100644
--- a/main.js
+++ b/main.js
@@ -16,6 +16,12 @@ window.onload = function(){
     else if (operator == "substract"){
       document.getElementById('ans').value = substract(num1, num2);
     }
+	else if (operator == "multiplicate"){
+      document.getElementById('ans').value = multiplicate(num1, num2);
+	 }
+	 else if (operator == "divide"){
+      document.getElementById('ans').value = divide(num1, num2);
+	  }
     else {
       alert("Bad operator!")
     }
diff --git a/test/.gitattributes b/test/.gitattributes
new file mode 100644
index 0000000..bdb0cab
--- /dev/null
+++ b/test/.gitattributes
@@ -0,0 +1,17 @@
+# Auto detect text files and perform LF normalization
+* text=auto
+
+# Custom for Visual Studio
+*.cs     diff=csharp
+
+# Standard to msysgit
+*.doc	 diff=astextplain
+*.DOC	 diff=astextplain
+*.docx diff=astextplain
+*.DOCX diff=astextplain
+*.dot  diff=astextplain
+*.DOT  diff=astextplain
+*.pdf  diff=astextplain
+*.PDF	 diff=astextplain
+*.rtf	 diff=astextplain
+*.RTF	 diff=astextplain
diff --git a/test/.gitignore b/test/.gitignore
new file mode 100644
index 0000000..96374c4
--- /dev/null
+++ b/test/.gitignore
@@ -0,0 +1,43 @@
+# Windows image file caches
+Thumbs.db
+ehthumbs.db
+
+# Folder config file
+Desktop.ini
+
+# Recycle Bin used on file shares
+$RECYCLE.BIN/
+
+# Windows Installer files
+*.cab
+*.msi
+*.msm
+*.msp
+
+# Windows shortcuts
+*.lnk
+
+# =========================
+# Operating System Files
+# =========================
+
+# OSX
+# =========================
+
+.DS_Store
+.AppleDouble
+.LSOverride
+
+# Thumbnails
+._*
+
+# Files that might appear on external disk
+.Spotlight-V100
+.Trashes
+
+# Directories potentially created on remote AFP share
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
diff --git a/test/test_calculator.js b/test/test_calculator.js
index 13f6205..e83c231 100644
--- a/test/test_calculator.js
+++ b/test/test_calculator.js
@@ -1,10 +1,34 @@
 var assert = require('assert');
 var cal = require('../calculator.js')
 
+
 describe('Calculator', function(){
   describe('add', function(){
     it('add', function(){
       assert.equal('2', cal.add(1, 1));
     })
   })
-})
+    describe('substract', function(){
+  	it('substract', function(){
+      assert.equal('0', cal.substract(1, 1));
+    })
+  })
+    describe('multiplicate', function(){
+	it('multiplicate', function(){
+      assert.equal('1', cal.multiplicate(1, 1));
+    })
+  })
+    describe('divide', function(){
+	it('divide', function(){
+      assert.equal('1', cal.divide(1, 1));
+    })
+  })
+  describe('returnvalue', function(){
+  it("returns the return value from the original function", function () {
+    var callback = sinon.stub().returns(42);
+    var proxy = once(callback);
+    assert.equals(proxy(), 42);
+ })
+  })
+});
+