diff --git a/calculator.php b/calculator.php
index 1011055..31d2f3f 100644
--- a/calculator.php
+++ b/calculator.php
@@ -1,29 +1,57 @@
 <?php
-class Calculator{
-  
-  public function add($numbers_to_add){
-      $sum = 0;
-      foreach($numbers_to_add as $num){
-          $sum = $num + $sum;
-      }
-      return $sum;
-  }
 
-  public function subtract($x, $y){
-      return $x - $y;
-  }
+/**
+ * Class Calculator
+ **/
+class Calculator
+{
+    /**
+     *
+     * @param [type] $numbers_to_add
+     * @return void
+     */
+    public function add($numbers_to_add)
+    {
+        $sum = 0;
+        foreach ($numbers_to_add as $num) {
+            $sum = $num + $sum;
+        }
+        return $sum;
+    }
 
-  public function multiply($numbers_to_multiply){
-      $product = 1;
-      foreach($numbers_to_multiply as $num){
-          $product = $num * $product;
-      }
-      return $product;
-  }
+    /**
+     *
+     * @param [type] $x
+     * @param [type] $y
+     * @return void
+     */
+    public function subtract($x, $y)
+    {
+        return $x - $y;
+    }
 
-  public function divide($x, $y){
-      return $x / $y;
-  }
+    /**
+     *
+     * @param [type] $numbers_to_multiply
+     * @return void
+     */
+    public function multiply($numbers_to_multiply)
+    {
+        $product = 1;
+        foreach ($numbers_to_multiply as $num) {
+            $product = $num * $product;
+        }
+        return $product;
+    }
 
+    /**
+     *
+     * @param [type] $x
+     * @param [type] $y
+     * @return void
+     */
+    public function divide($x, $y)
+    {
+        return $x / $y;
+    }
 }
-?>