diff --git a/Sprint-1/1-key-exercises/1-count.js b/Sprint-1/1-key-exercises/1-count.js
index 117bcb2b6e..1d10bd1fc8 100644
--- a/Sprint-1/1-key-exercises/1-count.js
+++ b/Sprint-1/1-key-exercises/1-count.js
@@ -4,3 +4,5 @@ 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 updates the variable count by taking its current value, adding 1 to it, and then assigning the new value back to count
+// The = sign assigns the value on the right to the variable on the left
diff --git a/Sprint-1/1-key-exercises/2-initials.js b/Sprint-1/1-key-exercises/2-initials.js
index 47561f6175..b252e8617e 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.charAt(0) + middleName.charAt(0) + lastName.charAt(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..a835e823d5 100644
--- a/Sprint-1/1-key-exercises/3-paths.js
+++ b/Sprint-1/1-key-exercises/3-paths.js
@@ -17,7 +17,8 @@ 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 lastDotIndex = filePath.lastIndexOf(".");
+const ext = filePath.slice(lastDotIndex);
 
-// 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..5dbc52298a 100644
--- a/Sprint-1/1-key-exercises/4-random.js
+++ b/Sprint-1/1-key-exercises/4-random.js
@@ -3,7 +3,12 @@ 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?
+// 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
+
+// Math.random() gives a random decimal number between 0 and 1
+// Math.random() * (maximum - minimum + 1) gives a random decimal number between 0 and 100
+// Math.floor() removes the decimal part, giving a whole number between 0 and 99
+// + minimum shifts the range up so the final result is between 1 and 100
diff --git a/Sprint-1/2-mandatory-errors/0.js b/Sprint-1/2-mandatory-errors/0.js
index cf6c5039f7..dec165fdb8 100644
--- a/Sprint-1/2-mandatory-errors/0.js
+++ b/Sprint-1/2-mandatory-errors/0.js
@@ -1,2 +1,10 @@
 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
+We don't want the computer to run these 2 lines - how can we solve this problem?
+
+//The error message displayed by Node.js is:
+//Uncaught SyntaxError: Unexpected identifier 'is'
+//This is a syntax error. It occurs because JavaScript is trying to interpret an
+//English sentence as JavaScript code. After reading the word 'This', the JavaScript
+//parser expects a valid JavaScript operator. Instead, it encounters another variable
+//name, 'is', which is not valid in that position according to JavaScript's syntax rules.
+//As a result, the parser throws the error Unexpected identifier 'is'.
\ No newline at end of file
diff --git a/Sprint-1/2-mandatory-errors/1.js b/Sprint-1/2-mandatory-errors/1.js
index 7a43cbea76..648da500ce 100644
--- a/Sprint-1/2-mandatory-errors/1.js
+++ b/Sprint-1/2-mandatory-errors/1.js
@@ -2,3 +2,7 @@
 
 const age = 33;
 age = age + 1;
+
+//The error message displayed by Node.js is:
+//Uncaught TypeError: Assignment to constant variable
+//The error happens because const creates a variable whose value cannot be reassigned.
\ No newline at end of file
diff --git a/Sprint-1/2-mandatory-errors/2.js b/Sprint-1/2-mandatory-errors/2.js
index e09b89831d..d315484ef3 100644
--- a/Sprint-1/2-mandatory-errors/2.js
+++ b/Sprint-1/2-mandatory-errors/2.js
@@ -1,5 +1,9 @@
 // Currently trying to print the string "I was born in Bolton" but it isn't working...
-// what's the error ?
+// what's the error?
 
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+
+//The error message displayed by Node.js is:
+//Uncaught ReferenceError: cityOfBirth is not defined
+//The error occurs because the variable 'cityofBirth' is used before it has been declared.
\ No newline at end of file
diff --git a/Sprint-1/2-mandatory-errors/3.js b/Sprint-1/2-mandatory-errors/3.js
index ec101884db..85df3de375 100644
--- a/Sprint-1/2-mandatory-errors/3.js
+++ b/Sprint-1/2-mandatory-errors/3.js
@@ -1,9 +1,14 @@
-const cardNumber = 4533787178994213;
+const cardNumber = "4533787178994213";
 const last4Digits = cardNumber.slice(-4);
 
-// The last4Digits variable should store the last 4 digits of cardNumber
-// However, the code isn't working
-// Before running the code, make and explain a prediction about why the code won't work
+// The last4Digits variable should store the last 4 digits of cardNumber.
+// However, the code isn't working.
+// Before running the code, make and explain a prediction about why the code won't work.
 // Then run the code and see what error it gives.
 // Consider: Why does it give this error? Is this what I predicted? If not, what's different?
-// Then try updating the expression last4Digits is assigned to, in order to get the correct value
+// Then try updating the expression last4Digits is assigned to, in order to get the correct value.
+
+//The error message displayed by Node.js is:
+//Uncaught TypeError: cardNumber.slice is not a function
+//The error occurs because slice() is a string method, but the variable 'cardNumber' is a number.
+//To get the last four digits, the number must be converted to a string.
\ No newline at end of file
diff --git a/Sprint-1/2-mandatory-errors/4.js b/Sprint-1/2-mandatory-errors/4.js
index 5f86c730bc..021c2d10df 100644
--- a/Sprint-1/2-mandatory-errors/4.js
+++ b/Sprint-1/2-mandatory-errors/4.js
@@ -1,2 +1,6 @@
 const 12HourClockTime = "8:53pm";
 const 24hourClockTime = "20:53";
+
+//The error message displayed by Node.js is:
+//Uncaught SyntaxError: Invalid or unexpected token
+//This error happens because JavaScript does not allow variable names to start with a number.
\ No newline at end of file