diff --git a/SpecRunner.html b/SpecRunner.html
index 0265dc18..645ab227 100644
--- a/SpecRunner.html
+++ b/SpecRunner.html
@@ -12,12 +12,12 @@
     <script src="jasmine/jasmine-2.8.0/boot.js"></script>
 
     <!--  Iterations 1 - 8 -->    
-    <script src="src/chronometer.js"></script>
-    <script src="tests/chronometer.spec.js"></script>
+    <!-- <script src="src/chronometer.js"></script> -->
+    <!-- <script src="tests/chronometer.spec.js"></script> -->
 
     <!-- Bonus Iteration 9: Centiseconds -->
-    <!-- <script src="src/chronometer-centiseconds.js"></script> -->
-    <!-- <script src="tests/chronometer-centiseconds.spec.js"></script> -->
+    <script src="src/chronometer-centiseconds.js"></script>
+    <script src="tests/chronometer-centiseconds.spec.js"></script>
 
   </head>
 
diff --git a/index.html b/index.html
index 32e914c7..4b64407d 100644
--- a/index.html
+++ b/index.html
@@ -38,10 +38,10 @@ <h3>Splits</h3>
 
 
   <!--  Iterations 1 - 8 -->
-  <script src="src/chronometer.js"></script>
+  <!-- <script src="src/chronometer.js"></script> -->
 
   <!-- Bonus Iteration 9: Centiseconds -->
-  <!-- <script src="src/chronometer-centiseconds.js"></script> -->
+  <script src="src/chronometer-centiseconds.js"></script>
 
   
   <!--  DOM manipulation logic -->
diff --git a/src/chronometer-centiseconds.js b/src/chronometer-centiseconds.js
index 8337b5b6..f69306b3 100644
--- a/src/chronometer-centiseconds.js
+++ b/src/chronometer-centiseconds.js
@@ -1,37 +1,52 @@
 class Chronometer {
   constructor() {
     // ... your code goes here
+    this.currentTime = 0;
+    this.intervalId = null;
   }
 
   start(printTimeCallback) {
     // ... your code goes here
+    this.intervalId = setInterval(() => {
+      this.currentTime++;
+      if (printTimeCallback) printTimeCallback(this.currentTime);
+      }, 10);
   }
 
   getMinutes() {
     // ... your code goes here
+    return Math.floor(this.currentTime / (60*100));
+
   }
 
   getSeconds() {
     // ... your code goes here
+    return Math.floor(this.currentTime/100 % 60);
   }
 
   getCentiseconds() {
     // ... your code goes here
+    return Math.floor(this.currentTime%100 );
+
   }
 
   computeTwoDigitNumber(value) {
     // ... your code goes here
+    return value < 10 ? `0${value}` :`${value}`;
   }
 
   stop() {
     // ... your code goes here
+    clearInterval(this.intervalId);
   }
 
   reset() {
     // ... your code goes here
+    this.currentTime = 0;
   }
 
   split() {
     // ... your code goes here
+    return `${this.computeTwoDigitNumber(this.getMinutes())}:${this.computeTwoDigitNumber(this.getSeconds())}.${this.computeTwoDigitNumber(this.getCentiseconds())}`;
   }
 }
diff --git a/src/chronometer.js b/src/chronometer.js
index 83c75bd2..900f7ede 100644
--- a/src/chronometer.js
+++ b/src/chronometer.js
@@ -1,33 +1,45 @@
 class Chronometer {
   constructor() {
     // ... your code goes here
+    this.currentTime = 0;
+    this.intervalId = null;
   }
 
   start(printTimeCallback) {
     // ... your code goes here
+    this.intervalId = setInterval(() => {
+      this.currentTime++;
+      if (printTimeCallback) printTimeCallback(this.currentTime);
+      }, 1000);
   }
 
   getMinutes() {
     // ... your code goes here
+    return Math.floor(this.currentTime / 60);
   }
 
   getSeconds() {
     // ... your code goes here
+    return Math.floor(this.currentTime % 60);
   }
 
   computeTwoDigitNumber(value) {
     // ... your code goes here
+    return value < 10 ? `0${value}` :`${value}`;
   }
 
   stop() {
     // ... your code goes here
+    clearInterval(this.intervalId);
   }
 
   reset() {
     // ... your code goes here
+    this.currentTime = 0;
   }
 
   split() {
     // ... your code goes here
+    return `${this.computeTwoDigitNumber(this.getMinutes())}:${this.computeTwoDigitNumber(this.getSeconds())}`;
   }
 }
diff --git a/src/index.js b/src/index.js
index 385caac5..294fd40f 100644
--- a/src/index.js
+++ b/src/index.js
@@ -84,4 +84,4 @@ btnRight.addEventListener('click', () => {
   } else {
     printSplit();
   }
-});
\ No newline at end of file
+});