modified the answer of 2-mandatory-errors 2.js

Author: leerogerfn

Sprint-2/2-mandatory-errors/3.js

@@ -1,5 +1,5 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const last4Digits = cardNumber.toString().slice(-4);
 
 console.log(last4Digits);