diff --git a/Sprint-1/1-key-exercises/1-count.js b/Sprint-1/1-key-exercises/1-count.js
index 117bcb2b6e..654dcb5c23 100644
--- a/Sprint-1/1-key-exercises/1-count.js
+++ b/Sprint-1/1-key-exercises/1-count.js
@@ -3,4 +3,4 @@ let count = 0;
 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
+// Line 3 calculates count + 1, then uses the = assignment operator to store the new value back into the count variable, changing its value from 0 to 1.
diff --git a/Sprint-1/1-key-exercises/2-initials.js b/Sprint-1/1-key-exercises/2-initials.js
index 47561f6175..6c8b24e69a 100644
--- a/Sprint-1/1-key-exercises/2-initials.js
+++ b/Sprint-1/1-key-exercises/2-initials.js
@@ -5,7 +5,6 @@ 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
-
diff --git a/Sprint-1/1-key-exercises/3-paths.js b/Sprint-1/1-key-exercises/3-paths.js
index ab90ebb28e..cca4eeeccc 100644
--- a/Sprint-1/1-key-exercises/3-paths.js
+++ b/Sprint-1/1-key-exercises/3-paths.js
@@ -17,7 +17,7 @@ console.log(`The base part of ${filePath} is ${base}`);
 // Create a variable to store the dir part of the filePath variable
 // Create a variable to store the ext part of the variable
 
-const dir = ;
-const ext = ;
+const dir = filePath.slice(0, lastSlashIndex);
+const ext = filePath.slice(filePath.lastIndexOf(".") + 1);
 
-// https://www.google.com/search?q=slice+mdn
\ No newline at end of file
+// https://www.google.com/search?q=slice+mdn
diff --git a/Sprint-1/1-key-exercises/4-random.js b/Sprint-1/1-key-exercises/4-random.js
index 292f83aabb..bb7123fc81 100644
--- a/Sprint-1/1-key-exercises/4-random.js
+++ b/Sprint-1/1-key-exercises/4-random.js
@@ -3,7 +3,9 @@ const maximum = 100;
 
 const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
 
-// 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
+// num stores a random whole number in the interval [1, 100].
+// Math.random() generates a random decimal in the interval [0, 1).
+// Math.floor() rounds the number down to the nearest whole number.
+// Adding minimum ensures the final result is in the interval [1, 100].
+
+console.log(num);
diff --git a/Sprint-1/2-mandatory-errors/0.js b/Sprint-1/2-mandatory-errors/0.js
index cf6c5039f7..044add7ac1 100644
--- a/Sprint-1/2-mandatory-errors/0.js
+++ b/Sprint-1/2-mandatory-errors/0.js
@@ -1,2 +1,2 @@
-This is just an instruction for the first activity - but it is just for human consumption
-We don't want the computer to run these 2 lines - how can we solve this problem?
\ No newline at end of file
+// This is just an instruction for the first activity - but it is just for human consumption
+// We don't want the computer to run these 2 lines - how can we solve this problem?
diff --git a/Sprint-1/2-mandatory-errors/1.js b/Sprint-1/2-mandatory-errors/1.js
index 7a43cbea76..031839b47d 100644
--- a/Sprint-1/2-mandatory-errors/1.js
+++ b/Sprint-1/2-mandatory-errors/1.js
@@ -1,4 +1,4 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
+let age = 33;
 age = age + 1;
diff --git a/Sprint-1/2-mandatory-errors/2.js b/Sprint-1/2-mandatory-errors/2.js
index e09b89831d..2865eb8a42 100644
--- a/Sprint-1/2-mandatory-errors/2.js
+++ b/Sprint-1/2-mandatory-errors/2.js
@@ -1,5 +1,5 @@
 // Currently trying to print the string "I was born in Bolton" but it isn't working...
 // what's the error ?
 
-console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`);
diff --git a/Sprint-1/2-mandatory-errors/3.js b/Sprint-1/2-mandatory-errors/3.js
index ec101884db..042ed1bfaa 100644
--- a/Sprint-1/2-mandatory-errors/3.js
+++ b/Sprint-1/2-mandatory-errors/3.js
@@ -1,5 +1,7 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const last4Digits = String(cardNumber).slice(-4);
+
+console.log(last4Digits);
 
 // The last4Digits variable should store the last 4 digits of cardNumber
 // However, the code isn't working
diff --git a/Sprint-1/2-mandatory-errors/4.js b/Sprint-1/2-mandatory-errors/4.js
index 5f86c730bc..f3637b3f31 100644
--- a/Sprint-1/2-mandatory-errors/4.js
+++ b/Sprint-1/2-mandatory-errors/4.js
@@ -1,2 +1,2 @@
-const 12HourClockTime = "8:53pm";
-const 24hourClockTime = "20:53";
+const twelveHourClockTime = "8:53pm";
+const twentyFourhourClockTime = "20:53";
diff --git a/Sprint-1/3-mandatory-interpret/1-percentage-change.js b/Sprint-1/3-mandatory-interpret/1-percentage-change.js
index e24ecb8e18..51925d55ad 100644
--- a/Sprint-1/3-mandatory-interpret/1-percentage-change.js
+++ b/Sprint-1/3-mandatory-interpret/1-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;
@@ -11,12 +11,26 @@ console.log(`The percentage change is ${percentageChange}`);
 
 // Read the code and then answer the questions below
 
-// a) How many function calls are there in this file? Write down all the lines where a function call is made
-
-// 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?
-
-// c) Identify all the lines that are variable reassignment statements
-
-// d) Identify all the lines that are variable declarations
-
-// e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// a) There are 5 function calls.
+// Line 4: carPrice.replaceAll(",", "")
+// Line 4: Number(...)
+// Line 5: priceAfterOneYear.replaceAll(",", "")
+// Line 5: Number(...)
+// Line 10: console.log(...)
+
+// b) There is no error in the current code because it has already been fixed.
+// The original error occurred because a comma was missing between the arguments in a function call.
+// The missing programming term is "arguments".
+// Adding the missing comma fixes the syntax error.
+
+// c) Variable reassignment statements:
+// Line 4: carPrice = Number(carPrice.replaceAll(",", ""));
+// Line 5: priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
+
+// d) Variable declarations:
+// Line 1: let carPrice = "10,000";
+// Line 2: let priceAfterOneYear = "8,543";
+// Line 7: const priceDifference = carPrice - priceAfterOneYear;
+// Line 8: const percentageChange = (priceDifference / carPrice) * 100;
+
+// e) The expression Number(carPrice.replaceAll(",", "")) first removes the comma from the string "10,000", producing "10000". It then converts that string into the number 10000 so it can be used in mathematical calculations.
\ No newline at end of file
diff --git a/Sprint-1/3-mandatory-interpret/2-time-format.js b/Sprint-1/3-mandatory-interpret/2-time-format.js
index 47d2395587..33db17f032 100644
--- a/Sprint-1/3-mandatory-interpret/2-time-format.js
+++ b/Sprint-1/3-mandatory-interpret/2-time-format.js
@@ -12,14 +12,25 @@ console.log(result);
 // For the piece of code above, read the code and then answer the following questions
 
 // a) How many variable declarations are there in this program?
+// Answer: 6
 
 // b) How many function calls are there?
+// Answer: 1 (console.log(result))
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
+// Answer: It returns the remainder after movieLength is divided by 60.
+// This gives the number of seconds left over after converting to minutes.
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+// Answer: It subtracts the remaining seconds from the total seconds,
+// then divides by 60 to calculate the total whole minutes.
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+// Answer: It represents the movie duration in hours:minutes:seconds.
+// A better name could be formattedTime or movieDuration.
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+// Answer: It works for most values, but it does not always display
+// the time in the standard format because single-digit minutes or
+// seconds are not padded with a leading zero (for example, 5 instead of 05).
diff --git a/Sprint-1/3-mandatory-interpret/3-to-pounds.js b/Sprint-1/3-mandatory-interpret/3-to-pounds.js
index 60c9ace69a..1f6e88d1f4 100644
--- a/Sprint-1/3-mandatory-interpret/3-to-pounds.js
+++ b/Sprint-1/3-mandatory-interpret/3-to-pounds.js
@@ -25,3 +25,21 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+
+// 2. const penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1):
+// Removes the "p" from the end of the string, leaving only the number (e.g. "399").
+
+// 3. const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0"):
+// Ensures the number has at least 3 digits by adding leading zeros if necessary.
+// For example, "5" becomes "005".
+
+// 4. const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2):
+// Takes all but the last two digits to get the pounds part.
+
+// 5. const pence = paddedPenceNumberString
+// .substring(paddedPenceNumberString.length - 2)
+// .padEnd(2, "0"):
+// Takes the last two digits as the pence part and makes sure it has two digits.
+
+// 6. console.log(`£${pounds}.${pence}`):
+// Prints the final price in pounds and pence, for example "£3.99".