diff --git a/.prettierrc.json b/.prettierrc.json
new file mode 100644
index 000000000..0967ef424
--- /dev/null
+++ b/.prettierrc.json
@@ -0,0 +1 @@
+{}
diff --git a/HOW-TO-SUBMIT.md b/HOW-TO-SUBMIT.md
index f9430423a..ee01474f3 100644
--- a/HOW-TO-SUBMIT.md
+++ b/HOW-TO-SUBMIT.md
@@ -10,7 +10,7 @@ You should use Git & Github to submit your coursework as a pull request.
 
 You can use the Github Desktop cheatsheet here to help you do this.
 
-[Github Desktop Cheatsheet](http://syllabus.codeyourfuture.io/git/cheatsheet)
+[Github Desktop Cheatsheet](http://syllabus.codeyourfuture.io/git/cheatsheet"
 
 You can also use this lesson to help you submit your coursework.
 
diff --git a/exercises/B-hello-world/exercise.js b/exercises/B-hello-world/exercise.js
index b179ee953..5fc7c5f47 100644
--- a/exercises/B-hello-world/exercise.js
+++ b/exercises/B-hello-world/exercise.js
@@ -1 +1,2 @@
-console.log("Hello world");
+console.log("Hello World");
+console.log("from Bolton")
diff --git a/exercises/C-variables/exercise.js b/exercises/C-variables/exercise.js
index a6bbb9786..f6e62af71 100644
--- a/exercises/C-variables/exercise.js
+++ b/exercises/C-variables/exercise.js
@@ -1,3 +1,5 @@
 // Start by creating a variable `greeting`
-
+var greeting = "Welcome to the Matrix"
+console.log(greeting);
+console.log(greeting);
 console.log(greeting);
diff --git a/exercises/D-strings/exercise.js b/exercises/D-strings/exercise.js
index 2cffa6a81..0827ed043 100644
--- a/exercises/D-strings/exercise.js
+++ b/exercises/D-strings/exercise.js
@@ -1,3 +1,5 @@
 // Start by creating a variable `message`
-
+var message = "Hello Neo";
+var messageType = typeof message;
 console.log(message);
+console.log(messageType);
diff --git a/exercises/E-strings-concatenation/exercise.js b/exercises/E-strings-concatenation/exercise.js
index 2cffa6a81..5b4181e8a 100644
--- a/exercises/E-strings-concatenation/exercise.js
+++ b/exercises/E-strings-concatenation/exercise.js
@@ -1,3 +1,5 @@
 // Start by creating a variable `message`
-
+var greetingStart = "Hello, my name is ";
+var name = "Maziar";
+var message = greetingStart + name;
 console.log(message);
diff --git a/exercises/F-strings-methods/exercise.js b/exercises/F-strings-methods/exercise.js
index 2cffa6a81..d7e36dbdb 100644
--- a/exercises/F-strings-methods/exercise.js
+++ b/exercises/F-strings-methods/exercise.js
@@ -1,3 +1,5 @@
 // Start by creating a variable `message`
-
+var name = "Maziar";
+var nameLength = name.length;
+var message= "My name is " + name + " and my name is " + nameLength + " characters long";
 console.log(message);
diff --git a/exercises/F-strings-methods/exercise2.js b/exercises/F-strings-methods/exercise2.js
index b4b46943d..f8f1c2b6b 100644
--- a/exercises/F-strings-methods/exercise2.js
+++ b/exercises/F-strings-methods/exercise2.js
@@ -1,3 +1,3 @@
 const name = " Daniel  ";
 
-console.log(message);
+console.log(name.trim());
diff --git a/exercises/G-numbers/exercise.js b/exercises/G-numbers/exercise.js
index 49e7bc00b..c4cb85ba8 100644
--- a/exercises/G-numbers/exercise.js
+++ b/exercises/G-numbers/exercise.js
@@ -1 +1,6 @@
 // Start by creating a variables `numberOfStudents` and `numberOfMentors`
+var numberOfStudents = 15;
+var numberOfMentors = 10;
+var numberTotal = numberOfStudents + numberOfMentors;
+
+console.log(numberTotal);
\ No newline at end of file
diff --git a/exercises/I-floats/exercise.js b/exercises/I-floats/exercise.js
index a5bbcd852..5d6808f60 100644
--- a/exercises/I-floats/exercise.js
+++ b/exercises/I-floats/exercise.js
@@ -1,2 +1,9 @@
 var numberOfStudents = 15;
 var numberOfMentors = 8;
+var percentageStudents = Math.round((numberOfStudents * 100) / (numberOfStudents + numberOfMentors));
+var percentageMentors = Math.round(
+  (numberOfMentors * 100) / (numberOfStudents + numberOfMentors)
+);
+
+console.log("Percentage students: " + percentageStudents + "%");
+console.log("Percentage mentors: " + percentageMentors + "%");
diff --git a/exercises/J-functions/exercise.js b/exercises/J-functions/exercise.js
index 0ae5850e5..0fc4c3655 100644
--- a/exercises/J-functions/exercise.js
+++ b/exercises/J-functions/exercise.js
@@ -1,5 +1,6 @@
 function halve(number) {
   // complete the function here
+  return number / 2;
 }
 
 var result = halve(12);
diff --git a/exercises/J-functions/exercise2.js b/exercises/J-functions/exercise2.js
index 82ef5e780..468d45596 100644
--- a/exercises/J-functions/exercise2.js
+++ b/exercises/J-functions/exercise2.js
@@ -1,5 +1,6 @@
 function triple(number) {
   // complete function here
+  return number * 3;
 }
 
 var result = triple(12);
diff --git a/exercises/K-functions-parameters/exercise.js b/exercises/K-functions-parameters/exercise.js
index 8d5db5e69..4ead6c68f 100644
--- a/exercises/K-functions-parameters/exercise.js
+++ b/exercises/K-functions-parameters/exercise.js
@@ -1,9 +1,10 @@
 // Complete the function so that it takes input parameters
-function multiply() {
+function multiply(num1 , num2) {
   // Calculate the result of the function and return it
+  return num1 + num2;
 }
 
 // Assign the result of calling the function the variable `result`
-var result = multiply(3, 4);
+var result = multiply(8, 4);
 
 console.log(result);
diff --git a/exercises/K-functions-parameters/exercise2.js b/exercises/K-functions-parameters/exercise2.js
index db7a8904b..4ac67f169 100644
--- a/exercises/K-functions-parameters/exercise2.js
+++ b/exercises/K-functions-parameters/exercise2.js
@@ -1,5 +1,7 @@
 // Declare your function first
-
+function divide(num1 , num2){
+    return num1/num2;
+}
 var result = divide(3, 4);
 
 console.log(result);
diff --git a/exercises/K-functions-parameters/exercise3.js b/exercises/K-functions-parameters/exercise3.js
index 537e9f4ec..aeaa596e5 100644
--- a/exercises/K-functions-parameters/exercise3.js
+++ b/exercises/K-functions-parameters/exercise3.js
@@ -1,4 +1,7 @@
 // Write your function here
+function createGreeting(name){
+    return "Hello, my name is " + name
+}
 
 var greeting = createGreeting("Daniel");
 
diff --git a/exercises/K-functions-parameters/exercise4.js b/exercises/K-functions-parameters/exercise4.js
index 7ab44589e..a10283ca4 100644
--- a/exercises/K-functions-parameters/exercise4.js
+++ b/exercises/K-functions-parameters/exercise4.js
@@ -1,5 +1,7 @@
 // Declare your function first
-
+function add(num1 , num2) {
+    return num1 + num2;
+}
 // Call the function and assign to a variable `sum`
-
+var sum = add(13 , 124);
 console.log(sum);
diff --git a/exercises/K-functions-parameters/exercise5.js b/exercises/K-functions-parameters/exercise5.js
index 7c5bcd605..98f8f654e 100644
--- a/exercises/K-functions-parameters/exercise5.js
+++ b/exercises/K-functions-parameters/exercise5.js
@@ -1,5 +1,7 @@
 // Declare your function here
-
+function createLongGreeting( name , age){
+    return "Hello, my name is " + name + " and I'm " + age + " years old"
+}
 const greeting = createLongGreeting("Daniel", 30);
 
 console.log(greeting);
diff --git a/exercises/L-functions-nested/README.md b/exercises/L-functions-nested/README.md
index 1c4ae9c8a..012be64e0 100644
--- a/exercises/L-functions-nested/README.md
+++ b/exercises/L-functions-nested/README.md
@@ -9,7 +9,7 @@ function getAgeInDays(age) {
   return age * 365;
 }
 
-function createCreeting(name, age) {
+function createGreeting(name, age) {
   var ageInDays = getAgeInDays(age);
   var message =
     "My Name is " + name + " and I was born over " + ageInDays + " days ago!";
diff --git a/exercises/L-functions-nested/exercise.js b/exercises/L-functions-nested/exercise.js
index a5d377442..236e595a1 100644
--- a/exercises/L-functions-nested/exercise.js
+++ b/exercises/L-functions-nested/exercise.js
@@ -3,3 +3,20 @@ var mentor2 = "Irina";
 var mentor3 = "Mimi";
 var mentor4 = "Rob";
 var mentor5 = "Yohannes";
+
+function nameUpppercase(name){
+    var nameUP = name.toUpperCase();
+    return nameUP;
+}
+function shoutyGreeting(name){
+    var greetingUP = "hello " + name;
+    return greetingUP.toUpperCase();
+}
+
+console.log(shoutyGreeting(mentor1));
+console.log(shoutyGreeting(mentor2));
+console.log(shoutyGreeting(mentor3));
+console.log(shoutyGreeting(mentor4));
+console.log(shoutyGreeting(mentor5));
+
+
diff --git a/extra/1-currency-conversion.js b/extra/1-currency-conversion.js
index 07391e15f..44ed4ad21 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) {
+  usPrice = price * 1.4;
+  return usPrice;
+}
 
 /*
   CURRENCY FORMATTING
@@ -15,7 +18,10 @@ 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) {
+  brlPrice = price * 0.99 *5.7;
+  return brlPrice.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 9c8ebc76a..09eafcac5 100644
--- a/extra/2-piping.js
+++ b/extra/2-piping.js
@@ -16,26 +16,31 @@
   the final result to the variable goodCode
 */
 
-function add() {
-
+function add(num1 , num2) {
+  return num1 + num2;
 }
 
-function multiply() {
-
+function multiply(n1 , n2 ) {
+  return n1 * n2;
 }
 
-function format() {
-
+function format(price) {
+  return "£" + price;
 }
 
 const startingValue = 2;
 
 // Why can this code be seen as bad practice? Comment your answer.
-let badCode =
+let badCode = startingValue + 10; function badCodes(badCode){return "£"}
 
 /* BETTER PRACTICE */
 
-let goodCode =
+  let goodCode = startingValue;
+
+function goodCodes(goodCode){
+  
+  return "£" + ((goodCode +10)*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/mandatory/1-syntax-errors.js b/mandatory/1-syntax-errors.js
index a10cc9ac2..c0ec00ea2 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 " + name "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;
+  total = a + b;
 
-  return "The total is total";
+  return "The total is " + total;
 }
 
 /* 
diff --git a/mandatory/2-logic-error.js b/mandatory/2-logic-error.js
index b90d41dd1..4902e77f2 100644
--- a/mandatory/2-logic-error.js
+++ b/mandatory/2-logic-error.js
@@ -1,16 +1,16 @@
 // The syntax for this function is valid but it has an error, find it and fix it.
 
 function trimWord(word) {
-  return wordtrim();
+  return word.trim();
 }
 
-function getWordLength(word) {
-  return "word".length();
+function getStringLength(word) {
+  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..3ad6b2682 100644
--- a/mandatory/3-function-output.js
+++ b/mandatory/3-function-output.js
@@ -1,15 +1,18 @@
 // Add comments to explain what this function does. You're meant to use Google!
+//Return a random number between 0 (inclusive) and 1 (exclusive):
 function getRandomNumber() {
   return Math.random() * 10;
 }
 
 // Add comments to explain what this function does. You're meant to use Google!
+//The concat() method is used to join two or more strings. This method does not change the existing strings, but returns a new string containing the text of the joined strings.
 function combine2Words(word1, word2) {
   return word1.concat(word2);
 }
 
 function concatenate(firstWord, secondWord, thirdWord) {
   // Write the body of this function to concatenate three words together.
+  return firstWord.concat(" ", secondWord," ", thirdWord);
   // 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..699bcd283 100644
--- a/mandatory/4-tax.js
+++ b/mandatory/4-tax.js
@@ -5,7 +5,10 @@
   Sales tax is 20% of the price of the product.
 */
 
-function calculateSalesTax() {}
+function calculateSalesTax(price) {
+  var tax = price *20 /100;
+  return price + tax;
+}
 
 /*
   CURRENCY FORMATTING
@@ -17,8 +20,15 @@ function calculateSalesTax() {}
   Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
 */
 
-function addTaxAndFormatCurrency() {}
+function addTaxAndFormatCurrency(price) {
+  tax = price * 20/100;
+  ulitamatePrice = price + tax;
+   return "£" + ulitamatePrice.toFixed(2);
 
+}
+
+
+ 
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====
diff --git a/package.json b/package.json
index 58555936d..f69a38267 100644
--- a/package.json
+++ b/package.json
@@ -14,11 +14,14 @@
     "url": "https://github.com/CodeYourFuture/JavaScript-Core-1-Coursework-Week1/issues"
   },
   "jest": {
-    "setupFilesAfterEnv": ["jest-extended"]
+    "setupFilesAfterEnv": [
+      "jest-extended"
+    ]
   },
   "homepage": "https://github.com/CodeYourFuture/JavaScript-Core-1-Coursework-Week1#readme",
   "devDependencies": {
     "jest": "^26.6.3",
-    "jest-extended": "^0.11.5"
+    "jest-extended": "^0.11.5",
+    "prettier": "2.3.1"
   }
 }