doc: documented the process to convert string in number to make math operations

Author: Grajales-K

Sprint-1/interpret/percentage-change.js

@@ -2,7 +2,7 @@ let carPrice = "10,000";
 let priceAfterOneYear = "8,543";
 
 carPrice = Number(carPrice.replaceAll(",", ""));
-priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
 
 const priceDifference = carPrice - priceAfterOneYear;
 const percentageChange = (priceDifference / carPrice) * 100;
@@ -13,10 +13,53 @@ 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
 
+    // There are 6 function calls in this file:
+    // Line 5: carPrice.replaceAll(",", "")
+    // Line 5: Number(carPrice.replaceAll(",", ""))
+    // Line 6: priceAfterOneYear.replaceAll(",", "")    
+    // Line 6: Number(priceAfterOneYear.replaceAll(",", ""))
+    // Line 10: console.log(`The percentage change is ${percentageChange}`) this is also 
+    // a function call to log the output as string to the console, then call the var percentageChange 
+
+
 // 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 was line 5, carPrice.replaceAll("," ""); missing the comma between the arguments
 
 // c) Identify all the lines that are variable reassignment statements
 
+    //line 4, line 5, 
+
 // d) Identify all the lines that are variable declarations
 
+    // line 1, line 2, line 7 and line 8
+
+
 // 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
+    //  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
+    //  now with the number cleaned we can convert this string in number with the method Number().
+
+
+
+
+
+    
+
+// let carPrice = "10,000";
+// let priceAfterOneYear = "8,543";
+
+// carPrice = Number(carPrice.replaceAll(",", ""));
+// console.log(carPrice); // the commas are removed and the string is converted to a number
+
+// priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
+// console.log(priceAfterOneYear); // the commas are removed and the string is converted to a number
+
+// const priceDifference = carPrice - priceAfterOneYear;
+// console.log(`The price difference is ${priceDifference}`);
+
+// const percentageChange = (priceDifference / carPrice) * 100;
+// console.log(`The percentage change is ${percentageChange}`);