diff --git a/index.js b/index.js
index ff28a6f9..f0fccf6f 100644
--- a/index.js
+++ b/index.js
@@ -1,22 +1,33 @@
+let a;
 class NumberArray {
-  constructor(numbers) {
-    this.numbers = numbers;
-  }
+    constructor(numbers) {
+            this.numbers = numbers;
+        }
+        /* getPositiveSum() {
+            let sum = 0;
+            for (let number of this.numbers) {
+                if (number > 0) {
+                    sum += number;
+                }
+            }
+            return sum;
+        } */
 
-  getPositiveSum() {
-    let sum = 0;
-    for (let number of this.numbers) {
-      if (number > 0) {
-        sum += number;
-      }
+    a = () => { /// using arrow function instead of traditional method
+        let sum = 0;
+        for (let number of this.numbers) {
+            if (number > 0) {
+                sum += number;
+            }
+        }
+        return sum;
     }
-    return sum;
-  }
 }
 
 const numbers = [2, -4, 6, -8, 10, -12];
 const numberArray = new NumberArray(numbers);
-const positiveSum = numberArray.getPositiveSum();
+const positiveSum = numberArray.a();
+console.log(positiveSum);
 
 // Input: [2, -4, 6, -8, 10, -12]
-// Output: 18
+// Output: 18
\ No newline at end of file