docs: documentation on how works the call in each functions and using methods like substring and padStart to add and take part or the string

Author: Grajales-K

Sprint-1/interpret/percentage-change.js

@@ -37,7 +37,7 @@ console.log(`The percentage change is ${percentageChange}`);
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
 
-    // This expresion will work in the parenthesis first, replacing all commas in the string carPrice
+    // This expression will work in the parenthesis first, replacing all commas in the string carPrice
     //  with an empty string, so basically returning the string 10000 instead of "10,000". 
     //  Then the Number() function will convert that string "10000" into a number 10000.
     //  secondly, js can not treat strings with commas as numbers, so we need to remove the commas

Sprint-1/interpret/to-pounds.js

@@ -1,20 +1,30 @@
+//declare a constant variable named penceString and assign it the string value "399p"
 const penceString = "399p";
 
 const penceStringWithoutTrailingP = penceString.substring(
   0,
   penceString.length - 1
 );
 
-const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
-const pounds = paddedPenceNumberString.substring(
-  0,
-  paddedPenceNumberString.length - 2
-);
+// here we remove the trailing 'p' from the string using the method substring() -1 of the total length
+console.log(penceStringWithoutTrailingP);
+
+
+//this line pads will contain a length of at least 3 characters, adding leading zeros if necessary
+const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");//399 or diff value -> 001
+
+// here we extract the pounds part of the string by taking all characters except the last two eg. 399 -> 3
+const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2); //3
+
+console.log(` this is the padStart adding 0 if its necessary ${paddedPenceNumberString}, and this here we just take the integer part ${pounds}`);
+
 
+// here we extract the pence part of the string by taking the last two characters eg. 399 -> 99
 const pence = paddedPenceNumberString
   .substring(paddedPenceNumberString.length - 2)
   .padEnd(2, "0");
 
+  console.log(` this is the pence part we take the last two digits ${pence}`);
 console.log(`£${pounds}.${pence}`);
 
 // This program takes a string representing a price in pence