Added MDN-based explanation,and documented variable declarations

Author: Zadri415

Sprint-1/3-mandatory-interpret/1-percentage-change.js

@@ -13,10 +13,25 @@ console.log(`The percentage change is ${percentageChange}`);
 
 // a) How many function calls are there in this file? Write down all the lines where a function call is made
 
+// Line 4 contains two function calls: replaceAll(",", "") & Number(...)
+// Line 5 also contains two function calls: replaceAll(",","") & Number(...)
+// Line 10 contains one function call: console.log()
+
 // b) Run the code and identify the line where the error is coming from - why is this error occurring? How can you fix this problem?
 
+// The error originates from line 5: SyntaxError: missing ) after argument list. According to MDN Web Docs, this occurs when there is a problem with how a function is called - typically caused by a typo, a missing separator (such as a comma), or an incorrectly formatted string within the argument list
+
 // c) Identify all the lines that are variable reassignment statements
+// Line 4: Reassignment (not a declaration)
+// Line 5: Reassignment (not a declaration)
 
 // d) Identify all the lines that are variable declarations
+// Line 1: Variable declaration using 'let'
+// Line 2: Variable declaration using 'let'
+// Line 7: Variable declaration using 'const'
+// Line 8: Variable declaration using 'const'
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+/* The expression Number(carPrice.replaceAll(",","")) first uses the String.prototype.replaceAll() method to remove all commas from the string stored in carPrice
+It then passes the resulting string to the Number() function, which converts it into a numeric value. According to MDN, replaceALL() returns a new string with all occurrences of a 
+specified substring replaced, and Number() converts its argument to a number or return NaN if the conversion fails */