Answer to 2-mandatory-errors/3.js code updated and explanation included as text

Author: DamianDL

Sprint-1/2-mandatory-errors/3.js

@@ -1,9 +1,16 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+//const last4Digits = cardNumber.slice(-4);
+
+
+// convert number → string, then slice the last 4 chars
+const last4 = cardNumber.toString().slice(-4);
+
+console.log(last4); // "4213"
 
 // The last4Digits variable should store the last 4 digits of cardNumber
 // However, the code isn't working
 // Before running the code, make and explain a prediction about why the code won't work
 // Then run the code and see what error it gives.
 // Consider: Why does it give this error? Is this what I predicted? If not, what's different?
 // Then try updating the expression last4Digits is assigned to, in order to get the correct value
+// cardNumber is a variable that holds a number, and numbers do not have a slice method. The slice method is used for strings and arrays, but not for numbers. To fix this error, we need to convert the cardNumber to a string before using the slice method. We can do this by using the toString() method on cardNumber, like this: cardNumber.toString().slice(-4). This will convert the number to a string and then allow us to use the slice method to get the last 4 digits.