diff --git a/Sprint-1/1-key-exercises/1-count.js b/Sprint-1/1-key-exercises/1-count.js
index 117bcb2b6..01ba66b16 100644
--- a/Sprint-1/1-key-exercises/1-count.js
+++ b/Sprint-1/1-key-exercises/1-count.js
@@ -4,3 +4,6 @@ count = count + 1;
 
 // Line 1 is a variable declaration, creating the count variable with an initial value of 0
 // Describe what line 3 is doing, in particular focus on what = is doing
+
+// We are updating the previous value of count to a new value. The = operator assigns a new value 
+// to the variable, meaning the data stored in memory is being changed.
\ No newline at end of file
diff --git a/Sprint-1/1-key-exercises/2-initials.js b/Sprint-1/1-key-exercises/2-initials.js
index 47561f617..db7d556f7 100644
--- a/Sprint-1/1-key-exercises/2-initials.js
+++ b/Sprint-1/1-key-exercises/2-initials.js
@@ -5,7 +5,8 @@ let lastName = "Johnson";
 // Declare a variable called initials that stores the first character of each string.
 // This should produce the string "CKJ", but you must not write the characters C, K, or J in the code of your solution.
 
-let initials = ``;
+let initials = `${firstName[0]}${middleName[0]}${lastName[0]}`;
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn
 
+console.log(initials);
\ No newline at end of file
diff --git a/Sprint-1/1-key-exercises/3-paths.js b/Sprint-1/1-key-exercises/3-paths.js
index ab90ebb28..ce44994db 100644
--- a/Sprint-1/1-key-exercises/3-paths.js
+++ b/Sprint-1/1-key-exercises/3-paths.js
@@ -14,10 +14,17 @@ const lastSlashIndex = filePath.lastIndexOf("/");
 const base = filePath.slice(lastSlashIndex + 1);
 console.log(`The base part of ${filePath} is ${base}`);
 
+
 // Create a variable to store the dir part of the filePath variable
+const dir = filePath.slice(0 ,lastSlashIndex + 1);
+console.log(`The div part of ${filePath} is ${dir}`);
+
+
 // Create a variable to store the ext part of the variable
+const lastDoteIndex = filePath.lastIndexOf(".");
+const ext = filePath.slice(lastDoteIndex);
+console.log(`The ext part of ${filePath} is ${ext}`);
 
-const dir = ;
-const ext = ;
+// https://www.google.com/search?q=slice+mdn
 
-// https://www.google.com/search?q=slice+mdn
\ No newline at end of file
+console.log(lastSlashIndex);
\ No newline at end of file
diff --git a/Sprint-1/1-key-exercises/4-random.js b/Sprint-1/1-key-exercises/4-random.js
index 292f83aab..e869f726b 100644
--- a/Sprint-1/1-key-exercises/4-random.js
+++ b/Sprint-1/1-key-exercises/4-random.js
@@ -3,7 +3,22 @@ const maximum = 100;
 
 const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
 
+console.log(num);
+
 // In this exercise, you will need to work out what num represents?
 // Try breaking down the expression and using documentation to explain what it means
 // It will help to think about the order in which expressions are evaluated
 // Try logging the value of num and running the program several times to build an idea of what the program is doing
+
+
+// order of math calculation - () > ** > * / % > + - (Parentheses first, then Exponentiation 
+// (right to left), then Multiplication/Division/Modulo (left to right), then Addition/Subtraction 
+// (left to right)).
+
+//Math.floor - returns the value of x rounded down to its nearest integer
+//Math.random - returns a random number 
+
+// First, the innermost parentheses are evaluated: (maximum - minimum + 1).
+// Then, the result is multiplied by the random number generated by the Math object.
+// Math.floor rounds the result down to the nearest integer.
+// Finally, the value is added to the minimum.
\ No newline at end of file
diff --git a/Sprint-2/1-key-errors/0.js b/Sprint-2/1-key-errors/0.js
index 653d6f5a0..e8eed5b42 100644
--- a/Sprint-2/1-key-errors/0.js
+++ b/Sprint-2/1-key-errors/0.js
@@ -1,5 +1,7 @@
 // Predict and explain first...
-//  =============> write your prediction here
+//  =============> this function takes a string and capitalize the first letter of each word, 
+// then returns the modified string. However. if the first character is a space  or a number,
+// the function must validate this edge case before processing to avoid unexpected results.
 
 // call the function capitalise with a string input
 // interpret the error message and figure out why an error is occurring
@@ -7,7 +9,16 @@
 function capitalise(str) {
   let str = `${str[0].toUpperCase()}${str.slice(1)}`;
   return str;
-}
+};
 
-// =============> write your explanation here
+console.log(capitalise("reza"));
+
+// =============> the parameter name and the variable are the same while causes this error 
 // =============> write your new code here
+
+function capitalise(str) {
+  const cap_string = `${str[0].toUpperCase()}${str.slice(1)}`;
+  return cap_string;
+};
+
+console.log(capitalise("reza"));
diff --git a/Sprint-2/1-key-errors/1.js b/Sprint-2/1-key-errors/1.js
index f2d56151f..8b50336e3 100644
--- a/Sprint-2/1-key-errors/1.js
+++ b/Sprint-2/1-key-errors/1.js
@@ -1,7 +1,9 @@
 // Predict and explain first...
 
 // Why will an error occur when this program runs?
-// =============> write your prediction here
+// =============> decimalNumber is already the name of the function parameter. 
+// You can't redeclare a variable with the same name in the same scope. and we do not even need to 
+// define a new variable 
 
 // Try playing computer with the example to work out what is going on
 
@@ -12,9 +14,19 @@ function convertToPercentage(decimalNumber) {
   return percentage;
 }
 
-console.log(decimalNumber);
+console.log(convertToPercentage(50));
+
+// =============> i removed the variable 
 
-// =============> write your explanation here
 
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+
+function convertToPercentage(decimalNumber) {
+  const percentage = `${decimalNumber * 100}%`;
+
+  return percentage;
+}
+
+
+console.log(convertToPercentage(50));
\ No newline at end of file
diff --git a/Sprint-2/1-key-errors/2.js b/Sprint-2/1-key-errors/2.js
index aad57f7cf..2438dc3f8 100644
--- a/Sprint-2/1-key-errors/2.js
+++ b/Sprint-2/1-key-errors/2.js
@@ -3,18 +3,47 @@
 
 // this function should square any number but instead we're going to get an error
 
-// =============> write your prediction of the error here
+// =============> the parameter can not be a number
+// Valid JavaScript Identifiers
+// Must start with a letter (a-z, A-Z), underscore (_), or dollar sign ($).
+// Cannot start with a number (0-9).
+// Can contain letters, numbers, underscores, or dollar signs after the first character.
+// Cannot be a reserved keyword (e.g., if, else, function, return).
 
-function square(3) {
-    return num * num;
-}
+// function square(3) {
+//     return num * num;
+// }
+
+// console.log(square(4));
 
 // =============> write the error message here
+// /Users/setup/Documents/CYF/Module-Structuring-and-Testing-Data/Sprint-2/1-key-errors/2.js:13
+// function square(3) {
+//                 ^
+
+// SyntaxError: Unexpected number
+//     at wrapSafe (node:internal/modules/cjs/loader:1662:18)
+//     at Module._compile (node:internal/modules/cjs/loader:1704:20)
+//     at Object..js (node:internal/modules/cjs/loader:1895:10)
+//     at Module.load (node:internal/modules/cjs/loader:1465:32)
+//     at Function._load (node:internal/modules/cjs/loader:1282:12)
+//     at TracingChannel.traceSync (node:diagnostics_channel:322:14)
+//     at wrapModuleLoad (node:internal/modules/cjs/loader:235:24)
+//     at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:171:5)
+//     at node:internal/main/run_main_module:36:49
+
+// Node.js v22.16.0
 
 // =============> explain this error message here
+// First Two Lines: Locate the file path and the specific line of code causing the error.
+// Following Lines: Display the type of error (SyntaxError) and its message.
 
 // Finally, correct the code to fix the problem
 
 // =============> write your new code here
+function square(num) {
+    return num * num;
+}
 
+console.log(square(4));
 
diff --git a/Sprint-2/2-mandatory-debug/0.js b/Sprint-2/2-mandatory-debug/0.js
index b27511b41..9a0153bf2 100644
--- a/Sprint-2/2-mandatory-debug/0.js
+++ b/Sprint-2/2-mandatory-debug/0.js
@@ -1,6 +1,8 @@
 // Predict and explain first...
 
 // =============> write your prediction here
+// the console.log inside the function will run but the one in global will raise the undefine error
+// we will get an undefine error because we are not retuning the value
 
 function multiply(a, b) {
   console.log(a * b);
@@ -9,6 +11,13 @@ function multiply(a, b) {
 console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
 
 // =============> write your explanation here
+// To use the final result of a function, we must return the value. Otherwise, it will raise an undefined error.
 
 // Finally, correct the code to fix the problem
 //  =============> write your new code here
+function multiply(a, b) {
+  const result = a * b;
+  return result; 
+}
+
+console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
\ No newline at end of file
diff --git a/Sprint-2/2-mandatory-debug/1.js b/Sprint-2/2-mandatory-debug/1.js
index 37cedfbcf..5673a7e51 100644
--- a/Sprint-2/2-mandatory-debug/1.js
+++ b/Sprint-2/2-mandatory-debug/1.js
@@ -1,5 +1,7 @@
 // Predict and explain first...
 //  =============> write your prediction here
+// Lines of code after a return statement are not executed, as the function exits immediately at that point
+
 
 function sum(a, b) {
   return;
@@ -9,5 +11,13 @@ function sum(a, b) {
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
 // =============> write your explanation here
+// we have to write the code inform of the return 
+
 // Finally, correct the code to fix the problem
 //  =============> write your new code here
+
+function sum(a, b) {
+  return a + b;
+}
+
+console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
\ No newline at end of file
diff --git a/Sprint-2/2-mandatory-debug/2.js b/Sprint-2/2-mandatory-debug/2.js
index 57d3f5dc3..0f1503561 100644
--- a/Sprint-2/2-mandatory-debug/2.js
+++ b/Sprint-2/2-mandatory-debug/2.js
@@ -2,6 +2,8 @@
 
 // Predict the output of the following code:
 // =============> Write your prediction here
+// Since we haven't defined a parameter for the function, it won't use any arguments we pass to it. 
+// Instead, every time we call the function, it will use the num value in its calculation. 
 
 const num = 103;
 
@@ -15,10 +17,21 @@ console.log(`The last digit of 806 is ${getLastDigit(806)}`);
 
 // Now run the code and compare the output to your prediction
 // =============> write the output here
-// Explain why the output is the way it is
+// we get the same output for all the consol,log
+
 // =============> write your explanation here
+// we get the same output because the Function is not using the argument we send 
+// but instead is using the number in the variable num 
+
 // Finally, correct the code to fix the problem
 // =============> write your new code here
-
 // This program should tell the user the last digit of each number.
 // Explain why getLastDigit is not working properly - correct the problem
+
+function getLastDigit(num) {
+  return num.toString().slice(-1);
+}
+
+console.log(`The last digit of 42 is ${getLastDigit(42)}`);
+console.log(`The last digit of 105 is ${getLastDigit(105)}`);
+console.log(`The last digit of 806 is ${getLastDigit(806)}`);
\ No newline at end of file
diff --git a/Sprint-2/3-mandatory-implement/1-bmi.js b/Sprint-2/3-mandatory-implement/1-bmi.js
index 17b1cbde1..9951c6fab 100644
--- a/Sprint-2/3-mandatory-implement/1-bmi.js
+++ b/Sprint-2/3-mandatory-implement/1-bmi.js
@@ -15,5 +15,9 @@
 // It should return their Body Mass Index to 1 decimal place
 
 function calculateBMI(weight, height) {
-    // return the BMI of someone based off their weight and height
-}
\ No newline at end of file
+  const height_squared = height * height;
+  const bmi = height_squared / weight;
+  return bmi.toFixed(1);
+}
+
+console.log(calculateBMI(83, 180));
diff --git a/Sprint-2/3-mandatory-implement/2-cases.js b/Sprint-2/3-mandatory-implement/2-cases.js
index 5b0ef77ad..0c53f3694 100644
--- a/Sprint-2/3-mandatory-implement/2-cases.js
+++ b/Sprint-2/3-mandatory-implement/2-cases.js
@@ -14,3 +14,12 @@
 // You will need to come up with an appropriate name for the function
 // Use the MDN string documentation to help you find a solution
 // This might help https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toUpperCase
+
+function upper_snake_case(string) {
+  const replace_space = string.replaceAll(" ", "_");
+  const to_uppercase = replace_space.toUpperCase();
+  return to_uppercase;
+}
+
+console.log(upper_snake_case("hello there"));
+console.log(upper_snake_case("lord of the rings"));
diff --git a/Sprint-2/3-mandatory-implement/3-to-pounds.js b/Sprint-2/3-mandatory-implement/3-to-pounds.js
index 6265a1a70..85c34859a 100644
--- a/Sprint-2/3-mandatory-implement/3-to-pounds.js
+++ b/Sprint-2/3-mandatory-implement/3-to-pounds.js
@@ -4,3 +4,29 @@
 // You will need to declare a function called toPounds with an appropriately named parameter.
 
 // You should call this function a number of times to check it works for different inputs
+
+function toPounds(penceString) {
+  const penceStringWithoutTrailingP = penceString.substring(
+    0,
+    penceString.length - 1
+  );
+
+  const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+  const pounds = paddedPenceNumberString.substring(
+    0,
+    paddedPenceNumberString.length - 2
+  );
+
+  const pence = paddedPenceNumberString
+    .substring(paddedPenceNumberString.length - 2)
+    .padEnd(2, "0");
+
+  return `£${pounds}.${pence}`;
+}
+
+// Test cases
+console.log(toPounds("399p"));  
+console.log(toPounds("9p"));    
+console.log(toPounds("1234p")); // £12.34 (assuming input can be longer than 3 digits)
+console.log(toPounds("0p"));    
+console.log(toPounds("5p"));    
\ No newline at end of file
diff --git a/Sprint-2/4-mandatory-interpret/time-format.js b/Sprint-2/4-mandatory-interpret/time-format.js
index 7c98eb0e8..98d87f30a 100644
--- a/Sprint-2/4-mandatory-interpret/time-format.js
+++ b/Sprint-2/4-mandatory-interpret/time-format.js
@@ -17,18 +17,20 @@ function formatTimeDisplay(seconds) {
 // Questions
 
 // a) When formatTimeDisplay is called how many times will pad be called?
-// =============> write your answer here
+// =============> 3
 
 // Call formatTimeDisplay with an input of 61, now answer the following:
 
 // b) What is the value assigned to num when pad is called for the first time?
-// =============> write your answer here
+// =============> 0
 
 // c) What is the return value of pad is called for the first time?
-// =============> write your answer here
+// =============> "00"
 
 // d) What is the value assigned to num when pad is called for the last time in this program?  Explain your answer
-// =============> write your answer here
+// =============> 1
+// Last pad call is pad(remainingSeconds), and remainingSeconds = 61 % 60 = 1
 
 // e) What is the return value assigned to num when pad is called for the last time in this program?  Explain your answer
-// =============> write your answer here
+// =============> "01"
+// pad(1) => "01" because "1".padStart(2, "0") results in "01"
diff --git a/Sprint-2/5-stretch-extend/format-time.js b/Sprint-2/5-stretch-extend/format-time.js
index 32a32e66b..e16a19dbd 100644
--- a/Sprint-2/5-stretch-extend/format-time.js
+++ b/Sprint-2/5-stretch-extend/format-time.js
@@ -3,11 +3,18 @@
 // Your task is to write tests for as many different groups of input data or edge cases as you can, and fix any bugs you find.
 
 function formatAs12HourClock(time) {
-  const hours = Number(time.slice(0, 2));
-  if (hours > 12) {
-    return `${hours - 12}:00 pm`;
+  const [hourStr, minuteStr] = time.split(":");
+  const hours = Number(hourStr);
+
+  let period = hours >= 12 ? "pm" : "am";
+  let displayHour = hours % 12;
+  if (displayHour === 0) {
+    displayHour = 12; // Handles 00:xx (midnight) and 12:xx (noon) 
   }
-  return `${time} am`;
+  // If you input "08:00" is allowed to pass
+  const paddedHour = hourStr.length === 2 && displayHour < 10 ? `0${displayHour}` : `${displayHour}`;
+
+  return `${paddedHour}:${minuteStr} ${period}`;
 }
 
 const currentOutput = formatAs12HourClock("08:00");
@@ -23,3 +30,10 @@ console.assert(
   currentOutput2 === targetOutput2,
   `current output: ${currentOutput2}, target output: ${targetOutput2}`
 );
+
+console.assert(formatAs12HourClock("00:00") === "12:00 am", "Midnight failed");
+console.assert(formatAs12HourClock("01:00") === "01:00 am", "1am failed");
+console.assert(formatAs12HourClock("08:00") === "08:00 am", "8am failed");
+console.assert(formatAs12HourClock("12:00") === "12:00 pm", "Noon failed");
+console.assert(formatAs12HourClock("13:00") === "01:00 pm", "1pm failed");
+console.assert(formatAs12HourClock("23:00") === "11:00 pm", "11pm failed");
\ No newline at end of file