Fix the typeOf variable to be able to use a method

Updated last4Digits assignment to convert cardNumber to a string before slicing.

Author: djebsoft

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

@@ -1,9 +1,18 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const last4Digits = (cardNumber.toString()).slice(-4);
 
 // 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
+
+/* my prediction about why the code isn't working is because either the new variable is declared with const keyword
+or the value of the variable cardNumber is a number not a string whereas the method .slice works only with strings */
+// the error it gives 'cardNumber.slice is not a function'
+// It gives this error because the computer assumes the coder is trying to invoke a function
+// yes it is my second prediction
+// updating the expression last4Digits is assigned to, in order to get the correct value is as follows
+// method one: puting the value of the variable cardNumber into quotes
+// method two: invoking the method .toString() to convert the type of the variable from number to string