diff --git a/Sprint-2/1-key-errors/0.js b/Sprint-2/1-key-errors/0.js
index 653d6f5a0..47bb9f618 100644
--- a/Sprint-2/1-key-errors/0.js
+++ b/Sprint-2/1-key-errors/0.js
@@ -1,13 +1,45 @@
 // Predict and explain first...
 //  =============> write your prediction here
+//  1.*Answer
+//  We have declared the "str" twice.It is already declared 
+//  in this function's parameter, hence causing the conflict. 
+//  Although "let" allows re-assignment of variables, the issue is redeclaration, 
+//  not reassignment.
+
 
 // call the function capitalise with a string input
+// 2.*Answer
+//  It throws an error detailed below;
+//  / home/justice/Documents/CYF/Module-Structuring-and-Testing-Data/Sprint-2/1-key-errors/tempCodeRunnerFile.js:2
+//  let str = `${str[0].toUpperCase()}${str.slice(1)}`;
+//      ^
+//  SyntaxError: Identifier 'str' has already been declared.
+
+
 // interpret the error message and figure out why an error is occurring
+//  3.*Answer
+//  The SyntaxError - Something is invalid that is not following 
+// Javascript rules.
+//  The identifier - a name used in the code has a problem and it 
+// lets m know which one in this case "str". It also let's me know
+// what the problem is in this case "str" has already been declared.
+
+//Fix this code:
+//  function capitalise(str) {
+//    let str = `${str[0].toUpperCase()}${str.slice(1)}`;
+//    return str;
+//  }
+
+// =============> write your explanation here
+//I have re-assigned the "str" variable and it now runs with no errors.
+// I also checked with console.log to see the output.
+
+// =============> write your new code here
 
 function capitalise(str) {
-  let str = `${str[0].toUpperCase()}${str.slice(1)}`;
+  str = `${str[0].toUpperCase()}${str.slice(1)}`;
   return str;
 }
+console.log(capitalise("justice"));
+
 
-// =============> write your explanation here
-// =============> write your new code here
diff --git a/Sprint-2/1-key-errors/1.js b/Sprint-2/1-key-errors/1.js
index f2d56151f..fc73766a5 100644
--- a/Sprint-2/1-key-errors/1.js
+++ b/Sprint-2/1-key-errors/1.js
@@ -1,20 +1,36 @@
 // Predict and explain first...
-
 // Why will an error occur when this program runs?
 // =============> write your prediction here
+// 1.*Answer
+// We have declared "decimalNumber" twice, which is not allowed.
+// It is already declared as a function parameter, causing a conflict.
+// console.log(decimalNumber) results in an error because it is outside
+// the function scope.It should call console.log(convertToPercentage(decimalNumber));
 
-// Try playing computer with the example to work out what is going on
-
-function convertToPercentage(decimalNumber) {
-  const decimalNumber = 0.5;
-  const percentage = `${decimalNumber * 100}%`;
-
-  return percentage;
-}
+//Try playing computer with the example to work out what is going on
+//    function convertToPercentage(decimalNumber) {
+//      const decimalNumber = 0.5;
+//      const percentage = `${decimalNumber * 100}%`;
 
-console.log(decimalNumber);
+//      return percentage;
+//    }
+//    console.log(decimalNumber);
 
 // =============> write your explanation here
+// 2.*Answer
+//  It throws an error detailed below;
+//   /home/justice/Documents/CYF/Module-Structuring-and-Testing-Data/Sprint-2/1-key-errors/1.js:12
+//   const decimalNumber = 0.5;
+//            ^
+// SyntaxError: Identifier 'decimalNumber' has already been declared
+
+// Removed the const declaration and returned the percentage calculation
+// using a template literal to append the percent symbol.
 
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+  function convertToPercentage(decimalNumber) {
+    return `${decimalNumber * 100}%`;
+  }
+
+  console.log(decimalNumber);
\ 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..38f22399d 100644
--- a/Sprint-2/1-key-errors/2.js
+++ b/Sprint-2/1-key-errors/2.js
@@ -1,20 +1,34 @@
 
 // Predict and explain first BEFORE you run any code...
 
-// this function should square any number but instead we're going to get an error
+// This function should square any number but instead we're going to get an error
 
 // =============> write your prediction of the error here
 
-function square(3) {
-    return num * num;
-}
+
+//  function square(3) {
+//    return num * num;
+//   }
 
 // =============> write the error message here
+//  /home/justice/Documents/CYF/Module-Structuring-and-Testing-Data/Sprint-2/1-key-errors/2.js:8
+//  function square(3) {
+//                  ^
+// The SyntaxError: Unexpected number 
 
 // =============> explain this error message here
 
+// This occurs because the number "3" is used as a function parameter. 
+// This is not valid syntax. A function parameter must be a valid variable name (an identifier),
+// not a number. JavaScript expects an identifier or no parameter at all.
+// That's why it throws a syntax error.
+//
 // Finally, correct the code to fix the problem
 
 // =============> write your new code here
 
+function square(num) {
+    return num * num;
+}
 
+console.log(square(3));
\ No newline at end of file
diff --git a/Sprint-2/2-mandatory-debug/0.js b/Sprint-2/2-mandatory-debug/0.js
index b27511b41..98a3df790 100644
--- a/Sprint-2/2-mandatory-debug/0.js
+++ b/Sprint-2/2-mandatory-debug/0.js
@@ -1,14 +1,30 @@
 // Predict and explain first...
-
+// The first console.log prints 320
+//It throws an error at console.log.
 // =============> write your prediction here
 
-function multiply(a, b) {
-  console.log(a * b);
-}
-
-console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
+//    function multiply(a, b) {
+//      console.log(a * b);
+//    }
+//    console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
 
 // =============> write your explanation here
+// It return the following output:
+// 320
+// The result of multiplying 10 and 32 is undefined
+
+// why?
+//the computer reads the values in the second console.log "multiply(10, 32)" and
+//the first console.log only prints the value, it does not store it.
+//the second console.log outputs the template literals and undefined
+// as it has no value to reach.
+
 
 // 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)}`);
+  //prints: The result of multiplying 10 and 32 is 320
\ 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..bd89836d9 100644
--- a/Sprint-2/2-mandatory-debug/1.js
+++ b/Sprint-2/2-mandatory-debug/1.js
@@ -1,13 +1,24 @@
 // Predict and explain first...
 //  =============> write your prediction here
 
-function sum(a, b) {
-  return;
-  a + b;
-}
+// The computer reads the return statement and stops executing the function.
+// So the function stops running before it reaches a + b.
+// Because of that, nothing is returned,
+// and the console.log prints the text and the values are undefined.
 
-console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
+// current output:The sum of 10 and 32 is undefined
 
-// =============> write your explanation here
+// Fix the code to make it work:
+  // function sum(a, b) {
+  //   return a + b;
+  // }
+  // console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
+
+//To make it work, I need to return a + b.
 // 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..6deb5b4cd 100644
--- a/Sprint-2/2-mandatory-debug/2.js
+++ b/Sprint-2/2-mandatory-debug/2.js
@@ -1,24 +1,54 @@
 // Predict and explain first...
+// The function does not take in any parameters, therefore it 
+// refers to the global const variable = 103 
+// So every console.log will print 3 every time. This function is not 
+// re-useable as it stands.
 
 // Predict the output of the following code:
 // =============> Write your prediction here
+//output is 3 for every console.log.
 
-const num = 103;
+// const num = 103;
 
-function getLastDigit() {
-  return num.toString().slice(-1);
-}
+// function getLastDigit() {
+//   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)}`);
+// 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)}`);
 
 // Now run the code and compare the output to your prediction
 // =============> write the output here
+// "/home/justice/Documents/CYF/Module-Structuring-and-Testing-Data/Sprint-2/2-mandatory-debug/2.js"
+// The last digit of 42 is 3
+// The last digit of 105 is 3
+// The last digit of 806 is 3
 // Explain why the output is the way it is
 // =============> write your explanation here
+// The function refers to the global const variable = 103 
+// So every console.log returns 3 every time.
+
 // Finally, correct the code to fix the problem
 // =============> write your new code here
 
+const num = 103;
+
+function getLastDigit(num) {
+  return num.toString().slice(-1);
+}
+
+console.log(`The last digit of 42 is ${getLastDigit(42)}`); 
+// prints: The last digit of 42 is 2
+console.log(`The last digit of 105 is ${getLastDigit(105)}`);
+//prints: The last digit of 105 is 5
+console.log(`The last digit of 806 is ${getLastDigit(806)}`);
+//prints: The last digit of 806 is 6
+
 // This program should tell the user the last digit of each number.
 // Explain why getLastDigit is not working properly - correct the problem
+// now the code works correctly
+
+// I declared "num" as a parameter of the function,
+// so the function now uses the value passed into it
+// instead of the global variable "num".
diff --git a/Sprint-2/3-mandatory-implement/1-bmi.js b/Sprint-2/3-mandatory-implement/1-bmi.js
index 17b1cbde1..9157a435d 100644
--- a/Sprint-2/3-mandatory-implement/1-bmi.js
+++ b/Sprint-2/3-mandatory-implement/1-bmi.js
@@ -13,7 +13,15 @@
 // Given someone's weight in kg and height in metres
 // Then when we call this function with the weight and height
 // It should return their Body Mass Index to 1 decimal place
+// bmi = weight / height**2).
 
+ // return the BMI of someone based off their weight and height
 function calculateBMI(weight, height) {
-    // return the BMI of someone based off their weight and height
-}
\ No newline at end of file
+    return  (weight/(Math.pow(height, 2))).toFixed(1);
+   
+}
+console.log(calculateBMI(100, 1.6)); //print 39.1
+console.log(calculateBMI(55, 1.6)); //print 21.5
+
+// I used Math.pow to raise the height to the power of 2 and .toFixed
+//for the number of decimal places.
\ No newline at end of file
diff --git a/Sprint-2/3-mandatory-implement/2-cases.js b/Sprint-2/3-mandatory-implement/2-cases.js
index 5b0ef77ad..f8e88850c 100644
--- a/Sprint-2/3-mandatory-implement/2-cases.js
+++ b/Sprint-2/3-mandatory-implement/2-cases.js
@@ -14,3 +14,14 @@
 // 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 changeToUpperCaseSnake(string) {
+    return string.toUpperCase().replaceAll(" ", "_");
+}
+
+console.log(changeToUpperCaseSnake("hello there"));
+console.log(changeToUpperCaseSnake("lord of the rings"));
+console.log(changeToUpperCaseSnake("learning to love Javascript"));
+
+// 1.Capitalise = .toUpperCase
+// 2.Find blank space = .replaceAll ("", ...)
+// 3.replace with _  = ,replaceAll (..., "_")
diff --git a/Sprint-2/3-mandatory-implement/3-to-pounds.js b/Sprint-2/3-mandatory-implement/3-to-pounds.js
index 6265a1a70..007f065bd 100644
--- a/Sprint-2/3-mandatory-implement/3-to-pounds.js
+++ b/Sprint-2/3-mandatory-implement/3-to-pounds.js
@@ -4,3 +4,37 @@
 // 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
+
+//Rewrite this code
+    // 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
+    // );
+
+    // const pence = paddedPenceNumberString
+    // .substring(paddedPenceNumberString.length - 2)
+    // .padEnd(2, "0");
+
+    // console.log(`£${pounds}.${pence}`);
+
+    //Updated code to make it re-useable:
+
+    function toPounds(fromPenceString) {
+        const penceString = fromPenceString.substring(0, fromPenceString.length -1);
+        const paddedString = penceString.padStart(3, "0");
+        const pounds = paddedString.substring(0, paddedString.length -2);
+        const pence = paddedString.substring(paddedString.length -2).padEnd(2, "0");
+        return `£${pounds}.${pence}`;
+    }
+    console.log(toPounds("399p")); // £3.99
+    console.log(toPounds("45p")); // £0.45
+    console.log(toPounds("1295p")); // £12.95
+    console.log(toPounds("5p")); // £0.05
\ 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..ff1d58574 100644
--- a/Sprint-2/4-mandatory-interpret/time-format.js
+++ b/Sprint-2/4-mandatory-interpret/time-format.js
@@ -11,6 +11,8 @@ function formatTimeDisplay(seconds) {
   return `${pad(totalHours)}:${pad(remainingMinutes)}:${pad(remainingSeconds)}`;
 }
 
+console.log(formatTimeDisplay(61));
+
 // You will need to play computer with this example - use the Python Visualiser https://pythontutor.com/visualize.html#mode=edit
 // to help you answer these questions
 
@@ -18,17 +20,28 @@ function formatTimeDisplay(seconds) {
 
 // a) When formatTimeDisplay is called how many times will pad be called?
 // =============> write your answer here
+//    It will be called 3 times. 1 for hours, 1 for minutes, 1 for seconds.
+//    return `${pad(totalHours)}:${pad(remainingMinutes)}:${pad(remainingSeconds)}`;
 
-// Call formatTimeDisplay with an input of 61, now answer the following:
+//    Call formatTimeDisplay with an input of 61, now answer the following:
+//    [Running] node "/home/justice/Documents/CYF/Module-Structuring-and-Testing-Data/Sprint-2/4-mandatory-interpret/time-format.js"
+//    00:01:01
 
 // b) What is the value assigned to num when pad is called for the first time?
 // =============> write your answer here
+//  The value is 0.
 
 // c) What is the return value of pad is called for the first time?
 // =============> write your answer here
+//  The return value is a string "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
-
-// e) What is the return value assigned to num when pad is called for the last time in this program?  Explain your answer
+//  The value is 1. When the input is 61, It is evaluating number of remaining seconds, 
+//  which equals 1.
+//  it is evaluating from left to right.
+// 
+//  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
+//  The return value is a string "01" because also because .padStart has been used to ensure that the 
+//  value displays as a minimum of 2 digits in this case if less than 2 digits add a leading "0".
\ No newline at end of file