diff --git a/README.md b/README.md
index 6611d00c3..5c862b7a6 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-# Coursework
+ # Coursework
 
 Like learning a musical instrument, programming requires daily practice.
 
@@ -10,7 +10,6 @@ If you think you need to do more practice with the basics, then you can find som
 
 ## Setting up your code editor
 
-
 There are some tools that will help you to write code. One of these, [Prettier](https://prettier.io/), formats your code, making it easier for you and others to read.
 
 ### 1. Install prettier
@@ -25,10 +24,9 @@ There are some tools that will help you to write code. One of these, [Prettier](
 - Search for `editor format`
 - Set `editor.formatOnSave` and `editor.formatOnPaste` to true
 
-
 ## Running the code/tests
 
-The files for the mandatory/extra exercises are intended to be run as jest tests. 
+The files for the mandatory/extra exercises are intended to be run as jest tests.
 
 - Once you have cloned the repository, run `npm install` once in the terminal to install jest (and any necessary dependencies).
 - To run the tests for all mandatory/extra exercises, run `npm test`
diff --git a/extra/1-currency-conversion.js b/extra/1-currency-conversion.js
index 75b3c6aab..8d3f576f2 100644
--- a/extra/1-currency-conversion.js
+++ b/extra/1-currency-conversion.js
@@ -5,7 +5,10 @@
   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 +18,13 @@ 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(PoundExchange) {
+  let exchangeRate = 5.7;
+  let fee = 0.01;
+  PoundExchange = (PoundExchange * exchangeRate) * (1 - fee);
+  return parseFloat(PoundExchange.toFixed(2));
+}
 
 /* ======= 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..19b2c5610 100644
--- a/extra/2-piping.js
+++ b/extra/2-piping.js
@@ -16,26 +16,29 @@
   the final result to the variable goodCode
 */
 
-function add() {
-
+function add(a,b) {
+return a + b;
 }
 
-function multiply() {
-
+function multiply(a,b) {
+return a*b;
 }
 
-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 addedValue = add(startingValue, 10);
+let multipliedValue = multiply(addedValue, 2);
+let goodCode = format(multipliedValue);
 
 /* ======= 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/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..ff5b064e1 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..7c18fbd5f 100644
--- a/mandatory/3-function-output.js
+++ b/mandatory/3-function-output.js
@@ -1,14 +1,20 @@
 // Add comments to explain what this function does. You're meant to use Google!
+//this function generates a random value between 0(inclusive) and 10(exlusive) everytime is called
+//Math.random generates a number between 0(inclusive ) and 1(exlusive) and then the function multiplies it with 10
 function getRandomNumber() {
   return Math.random() * 10;
 }
 
 // Add comments to explain what this function does. You're meant to use Google!
+//this function with combine/joins  two strings together and will return a 
+
 function combine2Words(word1, word2) {
   return word1.concat(word2);
 }
 
 function concatenate(firstWord, secondWord, thirdWord) {
+  return `${firstWord.toString()} ${secondWord.toString()} ${thirdWord.toString()}`;
+
   // 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.
 }
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index ba77c7ae2..bd01e6fd2 100644
--- a/mandatory/4-tax.js
+++ b/mandatory/4-tax.js
@@ -5,10 +5,15 @@
   Sales tax is 20% of the price of the product.
 */
 
-function calculateSalesTax() {}
+function calculateSalesTax(ProductPrice) {
+  let Tax = ProductPrice * 0.2;
+  let total = ProductPrice + Tax;
+  return total;
 
+}
 /*
   CURRENCY FORMATTING
+
   ===================
   The business has informed you that prices must have 2 decimal places
   They must also start with the currency symbol
@@ -17,8 +22,12 @@ function calculateSalesTax() {}
   Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
 */
 
-function addTaxAndFormatCurrency() {}
+function addTaxAndFormatCurrency(ProductPrice) {
+  let Tax = ProductPrice * 0.2;
+  let total = ProductPrice + Tax;
 
+  return `£${total.toFixed(2)}`;
+}
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====