diff --git a/exercises/B-hello-world/exercise.js b/exercises/B-hello-world/exercise.js
index b179ee953..cbd60bee5 100644
--- a/exercises/B-hello-world/exercise.js
+++ b/exercises/B-hello-world/exercise.js
@@ -1 +1,22 @@
 console.log("Hello world");
+
+//Try to`console.log()` something different.For example, 'Hello World. I just started learning JavaScript!'.
+console.log("Hello World. I just started learning JavaScript!");
+
+//Try to console.log() several things at once.
+console.log("Hello World.", "How are you?");
+
+// What happens when you get rid of the quote marks ?
+// Code: console.log(Hello World., How are you?)
+// Result: Syntax error
+
+// What happens when you console.log() just a number without quotes ?
+console.log(3);
+//result is the number 3
+
+
+//Overall result of code:
+// Hello world
+// Hello World.I just started learning JavaScript!
+// Hello World.How are you ?
+// 3
\ No newline at end of file
diff --git a/exercises/C-variables/exercise.js b/exercises/C-variables/exercise.js
index a6bbb9786..4aa5472cd 100644
--- a/exercises/C-variables/exercise.js
+++ b/exercises/C-variables/exercise.js
@@ -1,3 +1,5 @@
 // Start by creating a variable `greeting`
-
+let greeting = "Hello World!";
 console.log(greeting);
+console.log(greeting);
+console.log(greeting);
\ No newline at end of file
diff --git a/exercises/D-strings/exercise.js b/exercises/D-strings/exercise.js
index 2cffa6a81..ba6448068 100644
--- a/exercises/D-strings/exercise.js
+++ b/exercises/D-strings/exercise.js
@@ -1,3 +1,5 @@
 // Start by creating a variable `message`
-
+let message = "This is a string.";
 console.log(message);
+messageType = typeof message;
+console.log(messageType);
\ No newline at end of file
diff --git a/exercises/E-strings-concatenation/exercise.js b/exercises/E-strings-concatenation/exercise.js
index 2cffa6a81..2754f9dce 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`
-
+let name1 = "Omar";
+let message = "Hi " + name1 + ". Welcome aboard!";
 console.log(message);
+//Write a program that logs a message with a greeting and your name
\ No newline at end of file
diff --git a/exercises/F-strings-methods/exercise.js b/exercises/F-strings-methods/exercise.js
index 2cffa6a81..d5d3a7b89 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`
-
+let name1 = "Omar"
+let message = "My name is " + name1 + " and my name is " + name1.length + " characters long.";
 console.log(message);
+
diff --git a/exercises/F-strings-methods/exercise2.js b/exercises/F-strings-methods/exercise2.js
index b4b46943d..c1a232ffe 100644
--- a/exercises/F-strings-methods/exercise2.js
+++ b/exercises/F-strings-methods/exercise2.js
@@ -1,3 +1,3 @@
-const name = " Daniel  ";
-
+const name1 = " Omar  ";
+let message = "My name is " + name1.trim() + " and my name is " + name1.trim().length + " characters long.";
 console.log(message);
diff --git a/exercises/G-numbers/exercise.js b/exercises/G-numbers/exercise.js
index 49e7bc00b..5ccfa2dc4 100644
--- a/exercises/G-numbers/exercise.js
+++ b/exercises/G-numbers/exercise.js
@@ -1 +1,7 @@
 // Start by creating a variables `numberOfStudents` and `numberOfMentors`
+let numberOfStudents = 15;
+console.log("Number of students is: " + numberOfStudents);
+let numberOfMentors = 8;
+console.log("Number of mentors is: " + numberOfMentors);
+let message = "Total number of students and mentors is: " + (numberOfStudents + numberOfMentors);
+console.log(message);
diff --git a/exercises/I-floats/exercise.js b/exercises/I-floats/exercise.js
index a5bbcd852..353d70a23 100644
--- a/exercises/I-floats/exercise.js
+++ b/exercises/I-floats/exercise.js
@@ -1,2 +1,10 @@
 var numberOfStudents = 15;
 var numberOfMentors = 8;
+var totalNumber = numberOfStudents + numberOfMentors;
+let precisePercentageOfMentors = ((numberOfMentors / totalNumber) * 100);
+let precisePercentageOfStudents = ((numberOfStudents / totalNumber) * 100);
+let percentageOfStudents = Math.round(precisePercentageOfStudents);
+let percentageOfMentors = Math.round(precisePercentageOfMentors);
+console.log("Percentage students: " + percentageOfStudents + "%");
+console.log("Percentage mentors: " + percentageOfMentors + "%");
+
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..f416fda85 100644
--- a/exercises/K-functions-parameters/exercise.js
+++ b/exercises/K-functions-parameters/exercise.js
@@ -1,9 +1,8 @@
-// Complete the function so that it takes input parameters
-function multiply() {
-  // Calculate the result of the function and return it
+function multiply(num1, num2) {
+
+  return num1 * num2;
 }
 
-// Assign the result of calling the function the variable `result`
 var result = multiply(3, 4);
 
-console.log(result);
+console.log(result);
\ No newline at end of file
diff --git a/exercises/K-functions-parameters/exercise2.js b/exercises/K-functions-parameters/exercise2.js
index db7a8904b..db4e7fb53 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..059846268 100644
--- a/exercises/K-functions-parameters/exercise3.js
+++ b/exercises/K-functions-parameters/exercise3.js
@@ -1,5 +1,9 @@
 // Write your function here
-
+function createGreeting(name) {
+    return "Hello, my name is " + name;
+}
 var greeting = createGreeting("Daniel");
 
 console.log(greeting);
+
+// Write a function that takes a name (a string) and returns a greeting
\ No newline at end of file
diff --git a/exercises/K-functions-parameters/exercise4.js b/exercises/K-functions-parameters/exercise4.js
index 7ab44589e..e625347d3 100644
--- a/exercises/K-functions-parameters/exercise4.js
+++ b/exercises/K-functions-parameters/exercise4.js
@@ -1,5 +1,8 @@
 // Declare your function first
-
+function sumOfNumbers(num1, num2) {
+    return num1 + num2;
+}
+var sum = sumOfNumbers(13, 124);
 // Call the function and assign to a variable `sum`
 
 console.log(sum);
diff --git a/exercises/K-functions-parameters/exercise5.js b/exercises/K-functions-parameters/exercise5.js
index 7c5bcd605..73739f9fc 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(name1, age) {
+    return `Hello, my name is ${name1} and I'm ${age} years old.`;  
+}
 const greeting = createLongGreeting("Daniel", 30);
 
 console.log(greeting);
diff --git a/exercises/L-functions-nested/exercise.js b/exercises/L-functions-nested/exercise.js
index a5d377442..3f64deaec 100644
--- a/exercises/L-functions-nested/exercise.js
+++ b/exercises/L-functions-nested/exercise.js
@@ -3,3 +3,41 @@ var mentor2 = "Irina";
 var mentor3 = "Mimi";
 var mentor4 = "Rob";
 var mentor5 = "Yohannes";
+
+// Exercise 1:
+function percentageOfStudents(students, mentors) {
+    let total = students + mentors;
+    let percentageOfStudentsCalculation = (students / total) * 100; 
+    return Math.round(percentageOfStudentsCalculation);
+}
+function percentageOfMentors(students, mentors) {
+    let total = students + mentors;
+    let percentageOfMentorsCalculation = (mentors / total) * 100;
+    return Math.round(percentageOfMentorsCalculation);
+}
+function message(students, mentors) {
+    let messageForStudents = `Percentage students: ${percentageOfStudents(15,8)}%`
+        messageForMentors = `Percentage Mentors: ${percentageOfMentors(15,8)}%`;
+    return [messageForStudents, messageForMentors]
+}
+let messages = message(15, 8);
+console.log(messages);
+
+// ## Exercise 2
+function capitalLetterMessage(name) {
+    let shoutyComment = "Hello ".toUpperCase();
+    return shoutyComment; 
+}
+function capitalLetterName(name) {
+    let capitalName = capitalLetterMessage(name) + name.toUpperCase();
+    return capitalName;
+}
+console.log(capitalLetterName(mentor1));
+console.log(capitalLetterName(mentor2));
+console.log(capitalLetterName(mentor3));
+console.log(capitalLetterName(mentor4));
+console.log(capitalLetterName(mentor2));
+
+// - In `exercise2.js` you have been provided with the names of some mentors. Write a program that logs a shouty greeting to each one.
+// - Your program should include a function that spells their name in uppercase, and a function that creates a shouty greeting.
+// - Log each greeting to the console.
\ No newline at end of file
diff --git a/extra/1-currency-conversion.js b/extra/1-currency-conversion.js
index 70a2fe863..095a2d667 100644
--- a/extra/1-currency-conversion.js
+++ b/extra/1-currency-conversion.js
@@ -5,7 +5,12 @@
   Write a function that converts a price to USD (exchange rate is 1.4 $ to £)
 */
 
-function convertToUSD() {}
+function convertToUSD(poundValue) {
+  let convertedPrice = poundValue * 1.4; 
+  return convertedPrice;
+}
+let convertedUSDValue = convertToUSD()
+console.log(convertedUSDValue);
 
 /*
   CURRENCY FORMATTING
@@ -15,9 +20,15 @@ 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(poundValue) {
+  let convertedPrice = (5.7*0.99) * poundValue; 
+  return convertedPrice;
+}
+let convertedBRLValue = convertToBRL();
+console.log(convertedBRLValue);
+
 
-/* ======= TESTS - DO NOT MODIFY ===== 
+/* ======= TESTS - DO NOT MODIFY ===== `2
 There are some Tests in this file that will help you work out if your code is working.
 
 To run these tests type `node 1-currency-conversion` into your terminal
diff --git a/extra/2-piping.js b/extra/2-piping.js
index 067dd0f5b..8800acc84 100644
--- a/extra/2-piping.js
+++ b/extra/2-piping.js
@@ -16,22 +16,26 @@
   the final result to the variable goodCode
 */
 
-function add() {
-
+function add(startingValue, number2) {
+    let addedNumbers = startingValue + number2;
+    return addedNumbers;
 }
 
-function multiply() {
-
+function multiply(startingValue, number2) {
+    let multipliedNumbers = startingValue * number2;
+    return multipliedNumbers;
 }
 
-function format() {
-
+function format(number) {
+    let number1 = number.toString();
+    return number;
 }
 
 const startingValue = 2
 
 // Why can this code be seen as bad practice? Comment your answer.
-let badCode = 
+let foramtted = add(startingValue, 10) + multiply(startingValue, 2);
+let badCode = format(badCode);
 
 /* BETTER PRACTICE */
 
diff --git a/mandatory/1-syntax-errors.js b/mandatory/1-syntax-errors.js
index 0a21afd1b..7567bc588 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 3c578ad87..e5e326dc0 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();
+  return word.length;
 }
 
 function multiply(a, b, c) {
-  a * b * c;
-  return;
+  let multiplied = a * b * c;
+  return multiplied;
 }
 
 /* 
diff --git a/mandatory/3-function-output.js b/mandatory/3-function-output.js
index c9221a200..3b594a685 100644
--- a/mandatory/3-function-output.js
+++ b/mandatory/3-function-output.js
@@ -9,6 +9,8 @@ function s(w1, w2) {
 }
 
 function concatenate(firstWord, secondWord, thirdWord) {
+  let firstConcatenation = firstWord.concat(secondWord);
+  return firstConcatenation.concat(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.
 }
@@ -40,16 +42,16 @@ function test(test_name, actual, expected) {
 
 test(
   "concatenate function - case 1 works",
-  concatenate("code", "your", "future"),
+  concatenate("code ", "your ", "future"),
   "code your future"
 );
 test(
   "concatenate function - case 2 works",
-  concatenate("I", "like", "pizza"),
+  concatenate("I ", "like ", "pizza"),
   "I like pizza"
 );
 test(
   "concatenate function - case 3 works",
-  concatenate("I", "am", 13),
+  concatenate("I ", "am ", 13),
   "I am 13"
 );
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index c9e41c691..5767c8d7c 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(productPrice) {
+  let salesTax = productPrice + (productPrice * 0.2);
+  return salesTax
+}
 
 /*
   CURRENCY FORMATTING
@@ -17,8 +20,12 @@ 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 productPriceWithTax = calculateSalesTax(productPrice);
+  let formatCurrency = (new Intl.NumberFormat('en-GB', { style: 'currency', currency: 'GBP' }).format(productPriceWithTax))
+  return formatCurrency;
+  /*For the above formatting, I have used the following website: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat */
+}
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====