diff --git a/Sprint-3/1-key-errors/0.js b/Sprint-3/1-key-errors/0.js
index 653d6f5a0..17b65d00b 100644
--- a/Sprint-3/1-key-errors/0.js
+++ b/Sprint-3/1-key-errors/0.js
@@ -1,13 +1,20 @@
 // Predict and explain first...
-//  =============> write your prediction here
+//  =============> If the function will be called, it will print the first letter of the string
+// in capital with the rest of the word in lowercase
 
 // call the function capitalise with a string input
 // interpret the error message and figure out why an error is occurring
 
-function capitalise(str) {
+/* function capitalise(str) {
   let str = `${str[0].toUpperCase()}${str.slice(1)}`;
   return str;
+} */
+
+// =============> A SyntaxError was thrown because the str was used to name both the function parameter
+// and a new variable, which cannot happen in the same scope
+// =============>
+function capitalise(str) {
+  return `${str[0].toUpperCase()}${str.slice(1)}`;
 }
 
-// =============> write your explanation here
-// =============> write your new code here
+console.log(capitalise("mother"));
diff --git a/Sprint-3/1-key-errors/1.js b/Sprint-3/1-key-errors/1.js
index f2d56151f..8e4a749fd 100644
--- a/Sprint-3/1-key-errors/1.js
+++ b/Sprint-3/1-key-errors/1.js
@@ -1,20 +1,27 @@
 // Predict and explain first...
+// There will be another syntax error, because the same name is used for both the parameter and the variable
+// (decimalNumber)
 
 // Why will an error occur when this program runs?
-// =============> write your prediction here
+// =============>
+// We cannot redeclare a variable with the same name in the same scope.
 
 // Try playing computer with the example to work out what is going on
 
-function convertToPercentage(decimalNumber) {
+/* function convertToPercentage(decimalNumber) {
   const decimalNumber = 0.5;
   const percentage = `${decimalNumber * 100}%`;
 
   return percentage;
 }
-
-console.log(decimalNumber);
-
+*/
 // =============> 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(0.8));
diff --git a/Sprint-3/1-key-errors/2.js b/Sprint-3/1-key-errors/2.js
index aad57f7cf..fed0d1a76 100644
--- a/Sprint-3/1-key-errors/2.js
+++ b/Sprint-3/1-key-errors/2.js
@@ -1,20 +1,23 @@
-
 // Predict and explain first BEFORE you run any code...
 
 // this function should square any number but instead we're going to get an error
 
 // =============> write your prediction of the error here
+// I predict it will say 'num is not defined'
 
-function square(3) {
-    return num * num;
-}
+//  function square(3) {
+//     return num * num;
+// }
 
 // =============> write the error message here
-
+// SyntaxError: Unexpected number
 // =============> explain this error message here
-
+// Instead of a parameter name, the actual value was passed, resulting in an error;
 // Finally, correct the code to fix the problem
 
 // =============> write your new code here
 
-
+function square(num) {
+  return num * num;
+}
+console.log(square(6));
diff --git a/Sprint-3/2-mandatory-debug/0.js b/Sprint-3/2-mandatory-debug/0.js
index b27511b41..b675e6293 100644
--- a/Sprint-3/2-mandatory-debug/0.js
+++ b/Sprint-3/2-mandatory-debug/0.js
@@ -1,14 +1,21 @@
 // Predict and explain first...
 
-// =============> write your prediction here
+// =============>
+// Variables haven't been declared, so it will throw a reference error
 
-function multiply(a, b) {
+/* function multiply(a, b) {
   console.log(a * b);
 }
 
-console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
-
+console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`); */
 // =============> write your explanation here
-
+// It printed 32 because that particular console function is inside the multiply function (local), whereas the other one
+// is outside the scope and when we call the multiply function it comes up as undefined because nothing has been returned
+// inside of it.
 // 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-3/2-mandatory-debug/1.js b/Sprint-3/2-mandatory-debug/1.js
index 37cedfbcf..eb918729b 100644
--- a/Sprint-3/2-mandatory-debug/1.js
+++ b/Sprint-3/2-mandatory-debug/1.js
@@ -1,13 +1,21 @@
 // Predict and explain first...
 //  =============> write your prediction here
+// it will print the following: `The sum of 10 and 32 is undefined'
 
+/*
 function sum(a, b) {
   return;
   a + b;
 }
 
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
+*/
 
 // =============> write your explanation here
+// the function sum doesn't return any value. The arithmetic operation doesn't execute because it's defined after '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)}`);
diff --git a/Sprint-3/2-mandatory-debug/2.js b/Sprint-3/2-mandatory-debug/2.js
index 57d3f5dc3..fad01d643 100644
--- a/Sprint-3/2-mandatory-debug/2.js
+++ b/Sprint-3/2-mandatory-debug/2.js
@@ -2,8 +2,8 @@
 
 // Predict the output of the following code:
 // =============> Write your prediction here
-
-const num = 103;
+// it will not print the correct last digits
+/*const num = 103;
 
 function getLastDigit() {
   return num.toString().slice(-1);
@@ -12,13 +12,29 @@ function getLastDigit() {
 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
+/* 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
+
+// Because the method uses the num value which is 103.
 // 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
+// The function getLastDigit wasn't using intended parameters
diff --git a/Sprint-3/3-mandatory-implement/1-bmi.js b/Sprint-3/3-mandatory-implement/1-bmi.js
index 58b1085f1..17f01474c 100644
--- a/Sprint-3/3-mandatory-implement/1-bmi.js
+++ b/Sprint-3/3-mandatory-implement/1-bmi.js
@@ -15,5 +15,9 @@
 // It should return a string of their Body Mass Index to 1 decimal place
 
 function calculateBMI(weight, height) {
+  let bmi = weight / (height * height);
+  return bmi.toFixed(1);
+
   // return the BMI of someone based off their weight and height
 }
+console.log(`Your Bmi is ${calculateBMI(56, 1.66)}`);
diff --git a/Sprint-3/3-mandatory-implement/2-cases.js b/Sprint-3/3-mandatory-implement/2-cases.js
index 5b0ef77ad..97afe4bc9 100644
--- a/Sprint-3/3-mandatory-implement/2-cases.js
+++ b/Sprint-3/3-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 upperSnakeCaseMaker(str) {
+  let upperCased = str.toUpperCase();
+  let symbol = "_";
+  let underscored = upperCased.split(" ").join(symbol);
+  return underscored;
+}
+
+console.log(upperSnakeCaseMaker("the sun is shining"));
diff --git a/Sprint-3/3-mandatory-implement/3-to-pounds.js b/Sprint-3/3-mandatory-implement/3-to-pounds.js
index 10754da73..02235535b 100644
--- a/Sprint-3/3-mandatory-implement/3-to-pounds.js
+++ b/Sprint-3/3-mandatory-implement/3-to-pounds.js
@@ -4,3 +4,28 @@
 // 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}`;
+}
+
+// results of some different inputs: 0p -> £0.00, 3p -> £0.03, 50p -> £0.50, 170p -> £1.70, 1200p -> £12.00, 11000p -> £110.00
+console.log(toPounds("0p"));
+console.log(toPounds("3p"));
+console.log(toPounds("50p"));
+console.log(toPounds("170p"));
+console.log(toPounds("1200p"));
+console.log(toPounds("11000p"));
diff --git a/Sprint-3/4-mandatory-interpret/time-format.js b/Sprint-3/4-mandatory-interpret/time-format.js
index c0dd9c9a5..158cf6a82 100644
--- a/Sprint-3/4-mandatory-interpret/time-format.js
+++ b/Sprint-3/4-mandatory-interpret/time-format.js
@@ -21,18 +21,18 @@ 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 when it 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, because that's the actual value assigned to the num parameter (remainingSeconds is 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", the remainingSeconds is 1, which gets padded to "01" in the return value