diff --git a/extra/1-currency-conversion.js b/extra/1-currency-conversion.js
index 75b3c6aab..0e1d7f82b 100644
--- a/extra/1-currency-conversion.js
+++ b/extra/1-currency-conversion.js
@@ -5,7 +5,9 @@
   Write a function that converts a price to USD (exchange rate is 1.4 $ to £)
 */
 
-function convertToUSD() {}
+function convertToUSD(price) {
+  return price * 1.4;
+}
 
 /*
   CURRENCY CONVERSION
@@ -15,7 +17,10 @@ function convertToUSD() {}
   They have also decided that they should add a 1% fee to all foreign transactions, which means you only convert 99% of the £ to BRL.
 */
 
-function convertToBRL() {}
+function convertToBRL(price) {
+  return Math.round((price * 0.99) * 5.7 * 100) / 100;
+  
+}
 
 /* ======= TESTS - DO NOT MODIFY ===== 
 There are some Tests in this file that will help you work out if your code is working.
diff --git a/extra/2-piping.js b/extra/2-piping.js
index b4f8c4c1b..8d1bc1604 100644
--- a/extra/2-piping.js
+++ b/extra/2-piping.js
@@ -16,37 +16,42 @@
   the final result to the variable goodCode
 */
 
-function add() {
-
+function add(number1, number2) {
+  return number1 + number2;
 }
 
-function multiply() {
+function multiply(number1, number2) {
+  return number1 * number2;
 
 }
 
-function format() {
+function format(number) {
+  return `£${number}`;
 
 }
 
 const startingValue = 2;
 
+
 // Why can this code be seen as bad practice? Comment your answer.
-let badCode =
+let badCode = format(multiply(add(startingValue, 10), 2));
 
 /* BETTER PRACTICE */
 
-let goodCode =
+let addedNumbers = add(startingValue, 10);
+let multiplyedNumbers = multiply(addedNumbers, 2);
+let goodCode = format(multiplyedNumbers);
 
-/* ======= TESTS - DO NOT MODIFY ===== 
-There are some Tests in this file that will help you work out if your code is working.
+  /* ======= TESTS - DO NOT MODIFY ===== 
+  There are some Tests in this file that will help you work out if your code is working.
 
-To run the tests for just this one file, type `npm test -- --testPathPattern 2-piping` into your terminal
-(Reminder: You must have run `npm install` one time before this will work!)
-*/
+  To run the tests for just this one file, type `npm test -- --testPathPattern 2-piping` into your terminal
+  (Reminder: You must have run `npm install` one time before this will work!)
+  */
 
-test("add function - case 1 works", () => {
-  expect(add(1, 3)).toEqual(4);
-});
+  test("add function - case 1 works", () => {
+    expect(add(1, 3)).toEqual(4);
+  });
 
 test("add function - case 2 works", () => {
   expect(add(2.4, 5)).toEqual(7.4);
@@ -70,4 +75,4 @@ test("badCode variable correctly assigned", () => {
 
 test("goodCode variable correctly assigned", () => {
   expect(goodCode).toEqual("£24");
-});
+});
\ No newline at end of file
diff --git a/extra/3-magic-8-ball.js b/extra/3-magic-8-ball.js
index 46f65f928..37630c06b 100644
--- a/extra/3-magic-8-ball.js
+++ b/extra/3-magic-8-ball.js
@@ -45,10 +45,37 @@
 
 // This should log "The ball has shaken!"
 // and return the answer.
+const magicBallAnswers = [
+  "It is certain.",
+  "It is decidedly so.",
+  "Without a doubt.",
+  "Yes - definitely.",
+  "You may rely on it.",
+  "As I see it, yes.",
+  "Most likely.",
+  "Outlook good.",
+  "Yes.",
+  "Signs point to yes.",
+  "Reply hazy, try again.",
+  "Ask again later.",
+  "Better not tell you now.",
+  "Cannot predict now.",
+  "Concentrate and ask again.",
+  "Don 't count on it.",
+  "My reply is no.",
+  "My sources say no.",
+  "Outlook not so good.",
+  "Very doubtful."
+]
+
 function shakeBall() {
-  //Write your code in here
+  console.log("The ball has shaken!");
+  let randomNumber = Math.ceil(Math.random() * 19);
+  return magicBallAnswers[randomNumber];
 }
 
+const answer = shakeBall();
+
 /* 
   This function should say whether the answer it is given is
     - very positive
@@ -58,8 +85,23 @@ function shakeBall() {
 
   This function should expect to be called with any value which was returned by the shakeBall function.
 */
+
+
 function checkAnswer(answer) {
-  //Write your code in here
+  let result = '';
+  const number = magicBallAnswers.indexOf(answer);
+  if (number >= 0 && number < 5) {
+    result = 'very positive';
+  } else if (number >= 5 && number < 10) {
+    result = 'positive';
+  } else if (number >= 10 && number < 15) {
+    result = 'negative';
+  } else {
+    result = 'very negative';
+  }
+
+  return result;
+
 }
 
 /* 
@@ -115,4 +157,4 @@ test("checkAnswer works for `It is decidedly so.`", () => {
 
 test("checkAnswer works for `My reply is no.`", () => {
   expect(checkAnswer("My reply is no.")).toEqual("very negative");
-});
+});
\ No newline at end of file
diff --git a/mandatory/1-syntax-errors.js b/mandatory/1-syntax-errors.js
index d9e004465..dda84c3e5 100644
--- a/mandatory/1-syntax-errors.js
+++ b/mandatory/1-syntax-errors.js
@@ -1,16 +1,16 @@
 // There are syntax errors in this code - can you fix it to pass the tests?
 
-function addNumbers(a b c) {
+function addNumbers(a, b, c) {
   return a + b + c;
 }
 
-function introduceMe(name, age)
-  return `Hello, my {name}` is "and I am $age years old`;
+function introduceMe(name, age) {
+  return `Hello, my name is ${name} and I am ${age} years old`;
+}
 
 function getTotal(a, b) {
-  total = a ++ b;
-
-  return "The total is total";
+  total = a + b;
+  return `The total is ${total}`;
 }
 
 /* 
diff --git a/mandatory/2-logic-error.js b/mandatory/2-logic-error.js
index 9eb8c8cd7..85b4adff0 100644
--- a/mandatory/2-logic-error.js
+++ b/mandatory/2-logic-error.js
@@ -1,16 +1,15 @@
 // The syntax for these functions is valid but there are some errors, find them and fix them
 
 function trimWord(word) {
-  return wordtrim();
+  return word.trim();
 }
 
 function getStringLength(word) {
-  return "word".length();
+  return word.length;
 }
 
 function multiply(a, b, c) {
-  a * b * c;
-  return;
+   return a * b * c;
 }
 
 /* 
diff --git a/mandatory/3-function-output.js b/mandatory/3-function-output.js
index 5a953ba60..7784a71b3 100644
--- a/mandatory/3-function-output.js
+++ b/mandatory/3-function-output.js
@@ -1,9 +1,11 @@
 // Add comments to explain what this function does. You're meant to use Google!
+// This function is meant to return a random number between 0 and 9.9999
 function getRandomNumber() {
   return Math.random() * 10;
 }
 
 // Add comments to explain what this function does. You're meant to use Google!
+//This function is meant to join two strings togeather and return it as a new string.  
 function combine2Words(word1, word2) {
   return word1.concat(word2);
 }
@@ -11,6 +13,7 @@ function combine2Words(word1, word2) {
 function concatenate(firstWord, secondWord, thirdWord) {
   // Write the body of this function to concatenate three words together.
   // Look at the test case below to understand what this function is expected to return.
+  return `${firstWord} ${secondWord} ${thirdWord}`
 }
 
 /* 
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index ba77c7ae2..e498c12b5 100644
--- a/mandatory/4-tax.js
+++ b/mandatory/4-tax.js
@@ -5,7 +5,9 @@
   Sales tax is 20% of the price of the product.
 */
 
-function calculateSalesTax() {}
+function calculateSalesTax(price) {
+  return price * 1.20;
+}
 
 /*
   CURRENCY FORMATTING
@@ -17,7 +19,15 @@ function calculateSalesTax() {}
   Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
 */
 
-function addTaxAndFormatCurrency() {}
+function addTaxAndFormatCurrency(price) {
+  const priceWithTax = calculateSalesTax(price).toFixed(2);
+  return `£${priceWithTax}`;
+
+}
+
+
+
+
 
 /* 
 ===================================================
@@ -52,4 +62,4 @@ test("addTaxAndFormatCurrency for £17.50", () => {
 
 test("addTaxAndFormatCurrency for £34", () => {
   expect(addTaxAndFormatCurrency(34)).toEqual("£40.80");
-});
+});
\ No newline at end of file