diff --git a/Sprint-2/1-key-errors/0.js b/Sprint-2/1-key-errors/0.js
index 653d6f5a07..8a632b365c 100644
--- a/Sprint-2/1-key-errors/0.js
+++ b/Sprint-2/1-key-errors/0.js
@@ -1,6 +1,6 @@
 // Predict and explain first...
 //  =============> write your prediction here
-
+// I predict the code will give an error because inside the function we create a variable called str again.
 // call the function capitalise with a string input
 // interpret the error message and figure out why an error is occurring
 
@@ -9,5 +9,10 @@ function capitalise(str) {
   return str;
 }
 
+console.log(capitalise("hello"));
 // =============> write your explanation here
+// The error occurs because we are trying to declare a variable named str inside the function, but it is already declared as a parameter. This creates a conflict and results in a syntax error.
 // =============> write your new code here
+function capitalise(str) {
+  return `${str[0].toUpperCase()}${str.slice(1)}`;
+}
diff --git a/Sprint-2/1-key-errors/1.js b/Sprint-2/1-key-errors/1.js
index f2d56151f4..3d032c0d28 100644
--- a/Sprint-2/1-key-errors/1.js
+++ b/Sprint-2/1-key-errors/1.js
@@ -2,7 +2,7 @@
 
 // Why will an error occur when this program runs?
 // =============> write your prediction here
-
+// console.log(decimalNumber); will cause error because decimalNumber only exists inside the function.
 // Try playing computer with the example to work out what is going on
 
 function convertToPercentage(decimalNumber) {
@@ -15,6 +15,14 @@ function convertToPercentage(decimalNumber) {
 console.log(decimalNumber);
 
 // =============> write your explanation here
-
+//The error happens because the function already has a parameter called decimalNumber.
+//Creating another variable with the same name inside the function causes a conflict
 // 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(0.5));
diff --git a/Sprint-2/1-key-errors/2.js b/Sprint-2/1-key-errors/2.js
index aad57f7cfe..0b05dbee71 100644
--- a/Sprint-2/1-key-errors/2.js
+++ b/Sprint-2/1-key-errors/2.js
@@ -4,17 +4,26 @@
 // this function should square any number but instead we're going to get an error
 
 // =============> write your prediction of the error here
+// it is syntax error. 3 is a value not a variable name.
 
 function square(3) {
     return num * num;
 }
 
 // =============> write the error message here
+//function square(3) {
+                ^
 
+//SyntaxError: Unexpected number
 // =============> explain this error message here
+//The error is as I predicted. The function parameter should be a variable name, not a value. 
+//In this case, 3 is a value and cannot be used as a parameter name.
 
 // Finally, correct the code to fix the problem
 
 // =============> write your new code here
 
+function square(num) {
+    return num * num;
+}
 
diff --git a/Sprint-2/2-mandatory-debug/0.js b/Sprint-2/2-mandatory-debug/0.js
index b27511b417..85f0f75205 100644
--- a/Sprint-2/2-mandatory-debug/0.js
+++ b/Sprint-2/2-mandatory-debug/0.js
@@ -1,6 +1,7 @@
 // Predict and explain first...
 
 // =============> write your prediction here
+// I predict the code will give an error because the multiply function does not return a value.
 
 function multiply(a, b) {
   console.log(a * b);
@@ -9,6 +10,12 @@ function multiply(a, b) {
 console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
 
 // =============> write your explanation here
+//The function multiply(a, b) logs the result but does not return anything.
 
 // Finally, correct the code to fix the problem
 //  =============> write your new code here
+function multiply(a, b) {
+  return a * b;
+}
+
+console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
diff --git a/Sprint-2/2-mandatory-debug/1.js b/Sprint-2/2-mandatory-debug/1.js
index 37cedfbcfd..2867b63446 100644
--- a/Sprint-2/2-mandatory-debug/1.js
+++ b/Sprint-2/2-mandatory-debug/1.js
@@ -1,6 +1,6 @@
 // Predict and explain first...
 //  =============> write your prediction here
-
+// I predict the code will give an error because the sum function does not return a value.
 function sum(a, b) {
   return;
   a + b;
@@ -9,5 +9,12 @@ function sum(a, b) {
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
 // =============> write your explanation here
+// The function sum(a, b) has a return statement that does not return the result of a + b.
+// Instead, it returns undefined because the return statement is followed by a semicolon, which ends the statement before the addition operation is executed.
 // 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)}`);
diff --git a/Sprint-2/2-mandatory-debug/2.js b/Sprint-2/2-mandatory-debug/2.js
index 57d3f5dc35..f676bb83f2 100644
--- a/Sprint-2/2-mandatory-debug/2.js
+++ b/Sprint-2/2-mandatory-debug/2.js
@@ -2,6 +2,7 @@
 
 // Predict the output of the following code:
 // =============> Write your prediction here
+//The function has no parameter, so it cannot use input values like 42, 105, 806
 
 const num = 103;
 
@@ -15,10 +16,21 @@ 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
+// The out will be the last digit of 103 for all three console.log statements, because the function getLastDigit() is using the variable num which is set to 103, instead of using the input values passed to it.
 // Explain why the output is the way it is
 // =============> write your explanation here
+//The function is not using the value passed into it.
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+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)}`);
 
 // This program should tell the user the last digit of each number.
 // Explain why getLastDigit is not working properly - correct the problem
+// If a function should work with different values → it must have parameters.
+// Otherwise it will always use the same fixed value
diff --git a/Sprint-2/3-mandatory-implement/1-bmi.js b/Sprint-2/3-mandatory-implement/1-bmi.js
index 17b1cbde1b..e29fe7ad69 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
+  // return the BMI of someone based off their weight and height
+  const bmi = weight / (height * height);
+  return Number(bmi.toFixed(1));
+}
+console.log(calculateBMI(72, 1.76));
+// just to check the function is working correctly, and it works.
diff --git a/Sprint-2/3-mandatory-implement/2-cases.js b/Sprint-2/3-mandatory-implement/2-cases.js
index 5b0ef77ad9..f3a5dd02a5 100644
--- a/Sprint-2/3-mandatory-implement/2-cases.js
+++ b/Sprint-2/3-mandatory-implement/2-cases.js
@@ -14,3 +14,9 @@
 // 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 toUpperSnakeCase(str) {
+  return str.toUpperCase().replaceAll(" ", "_");
+}
+console.log(toUpperSnakeCase("hello there"));
+console.log(toUpperSnakeCase("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 6265a1a703..9f058226f2 100644
--- a/Sprint-2/3-mandatory-implement/3-to-pounds.js
+++ b/Sprint-2/3-mandatory-implement/3-to-pounds.js
@@ -4,3 +4,26 @@
 // 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}`;
+}
+console.log(toPounds("123p"));
+console.log(toPounds("5p"));
+console.log(toPounds("0p"));
diff --git a/Sprint-2/4-mandatory-interpret/time-format.js b/Sprint-2/4-mandatory-interpret/time-format.js
index 17127bc01e..cebaf1ce03 100644
--- a/Sprint-2/4-mandatory-interpret/time-format.js
+++ b/Sprint-2/4-mandatory-interpret/time-format.js
@@ -22,17 +22,22 @@ function formatTimeDisplay(seconds) {
 
 // a) When formatTimeDisplay is called how many times will pad be called?
 // =============> write your answer here
+// three times- hours, minutes, seconds
 
 // 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
+// num = 0, because totalHours = 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
+//  num = 1, because remainingSeconds = 1.
 
 // e) What is the return value of pad when it is called for the last time in this program?  Explain your answer
 // =============> write your answer here
+// "01", because the function adds a leading zero to the single-digit number 1, resulting in the string "01".
diff --git a/Sprint-2/5-stretch-extend/format-time.js b/Sprint-2/5-stretch-extend/format-time.js
index 32a32e66b8..f033eecf1f 100644
--- a/Sprint-2/5-stretch-extend/format-time.js
+++ b/Sprint-2/5-stretch-extend/format-time.js
@@ -23,3 +23,24 @@ console.assert(
   currentOutput2 === targetOutput2,
   `current output: ${currentOutput2}, target output: ${targetOutput2}`
 );
+
+const currentOutput3 = formatAs12HourClock("00:00");
+const targetOutput3 = "12:00 am";
+console.assert(
+  currentOutput3 === targetOutput3,
+  `current output: ${currentOutput3}, target output: ${targetOutput3}`
+);
+
+const currentOutput4 = formatAs12HourClock("12:00");
+const targetOutput4 = "12:00 pm";
+console.assert(
+  currentOutput4 === targetOutput4,
+  `current output: ${currentOutput4}, target output: ${targetOutput4}`
+);
+
+console.log(formatAs12HourClock("08:00"));
+console.log(formatAs12HourClock("23:00"));
+console.log(formatAs12HourClock("00:00"));
+console.log(formatAs12HourClock("12:00"));
+
+//The function did not handle the edge cases 00:00 and 12:00.