diff --git a/exercises/B-hello-world/exercise.js b/exercises/B-hello-world/exercise.js
index b179ee953..d7bdcb9c8 100644
--- a/exercises/B-hello-world/exercise.js
+++ b/exercises/B-hello-world/exercise.js
@@ -1 +1,12 @@
 console.log("Hello world");
+console.log("Hello everyone. I am now trying using console.log with different kind of inputs.");
+console.log(23);
+console.log(("is this(using a nested paranthesis) gonna cause an error?"));
+console.log("My name is", "Omer");
+console.log((("I am now using three paranthesis inside console.log.")));
+
+const name = "omer";
+const hobby  = "coding";
+
+console.log("Hi everyone. My name is", name, ", and my hobby is", hobby);
+console.log("Hi everyone. My name is" + name + "and my hobby is" + hobby);
diff --git a/exercises/C-variables/exercise.js b/exercises/C-variables/exercise.js
index a6bbb9786..ab0f32a84 100644
--- a/exercises/C-variables/exercise.js
+++ b/exercises/C-variables/exercise.js
@@ -1,3 +1,8 @@
 // Start by creating a variable `greeting`
 
+const greeting = "Hello world";
+
+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..bebb533d6 100644
--- a/exercises/D-strings/exercise.js
+++ b/exercises/D-strings/exercise.js
@@ -1,3 +1,7 @@
 // Start by creating a variable `message`
 
+const message = "This is a string";
+const 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..98df479d8 100644
--- a/exercises/E-strings-concatenation/exercise.js
+++ b/exercises/E-strings-concatenation/exercise.js
@@ -1,3 +1,7 @@
 // Start by creating a variable `message`
 
+const greeting = "Hello, my name is ";
+const name = "Omer";
+const message = greeting + name;
+
 console.log(message);
diff --git a/exercises/F-strings-methods/exercise.js b/exercises/F-strings-methods/exercise.js
index 2cffa6a81..c7d492aae 100644
--- a/exercises/F-strings-methods/exercise.js
+++ b/exercises/F-strings-methods/exercise.js
@@ -1,3 +1,8 @@
 // Start by creating a variable `message`
 
+const name = "Omer";
+const nameLength = name.length;
+const message = `   My name is ${name} and my name is ${nameLength} characters long.  `;
+
 console.log(message);
+console.log(message.trim());
diff --git a/exercises/F-strings-methods/exercise2.js b/exercises/F-strings-methods/exercise2.js
index b4b46943d..5bced5523 100644
--- a/exercises/F-strings-methods/exercise2.js
+++ b/exercises/F-strings-methods/exercise2.js
@@ -1,3 +1,7 @@
 const name = " Daniel  ";
+const nameTrim = name.trim();
+const nameLength = name.length;
+const message = `My name is ${nameTrim} and my name is 6 characters long`;
 
 console.log(message);
+
diff --git a/exercises/G-numbers/exercise.js b/exercises/G-numbers/exercise.js
index 49e7bc00b..10e49ed5f 100644
--- a/exercises/G-numbers/exercise.js
+++ b/exercises/G-numbers/exercise.js
@@ -1 +1,8 @@
 // Start by creating a variables `numberOfStudents` and `numberOfMentors`
+
+const numberOfStudents = 15;
+const numberOfMentors = 8;
+const message = `Number of students: ${numberOfStudents}
+Number of mentors: ${numberOfMentors}
+Total number of students and mentors: ${numberOfStudents + numberOfMentors}`;
+console.log(message);
diff --git a/exercises/I-floats/exercise.js b/exercises/I-floats/exercise.js
index a5bbcd852..212abbceb 100644
--- a/exercises/I-floats/exercise.js
+++ b/exercises/I-floats/exercise.js
@@ -1,2 +1,18 @@
-var numberOfStudents = 15;
-var numberOfMentors = 8;
+const numberOfStudents = 15;
+const numberOfMentors = 8;
+const studentsPercentage = Math.round(100 *(numberOfStudents / (numberOfStudents + numberOfMentors)));
+const mentorsPercentage = Math.round(100 *
+  (numberOfMentors / (numberOfStudents + numberOfMentors)));
+
+const message = `Percentage students: ${studentsPercentage}%
+Percentage mentors: ${mentorsPercentage}%`;
+
+const message2 = `Percentage students: ${Math.round(
+  100 * (numberOfStudents / (numberOfStudents + numberOfMentors))
+)}%
+Percentage mentors: ${Math.round(
+  100 * (numberOfMentors / (numberOfStudents + numberOfMentors))
+)}%`;
+
+console.log(message);
+console.log(message2);
diff --git a/exercises/J-functions/exercise.js b/exercises/J-functions/exercise.js
index 0ae5850e5..aa63cf3c2 100644
--- a/exercises/J-functions/exercise.js
+++ b/exercises/J-functions/exercise.js
@@ -1,7 +1,10 @@
 function halve(number) {
   // complete the function here
+  return number / 2;
 }
 
-var result = halve(12);
+const result = halve(12);
+const result2 = halve(36);
 
 console.log(result);
+console.log(result2);
diff --git a/exercises/J-functions/exercise2.js b/exercises/J-functions/exercise2.js
index 82ef5e780..552e61635 100644
--- a/exercises/J-functions/exercise2.js
+++ b/exercises/J-functions/exercise2.js
@@ -1,7 +1,9 @@
 function triple(number) {
   // complete function here
+  return number * 3;
 }
 
-var result = triple(12);
+const result = triple(12);
 
 console.log(result);
+
diff --git a/exercises/K-functions-parameters/exercise.js b/exercises/K-functions-parameters/exercise.js
index 8d5db5e69..d1e24aa82 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);
+const result = multiply(3, 4);
 
 console.log(result);
diff --git a/exercises/K-functions-parameters/exercise2.js b/exercises/K-functions-parameters/exercise2.js
index db7a8904b..d3a3988d6 100644
--- a/exercises/K-functions-parameters/exercise2.js
+++ b/exercises/K-functions-parameters/exercise2.js
@@ -1,5 +1,9 @@
 // Declare your function first
+function divide (num1, num2) {
+    return num1 / num2;
+}
 
-var result = divide(3, 4);
+
+const 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..76e33a9d9 100644
--- a/exercises/K-functions-parameters/exercise3.js
+++ b/exercises/K-functions-parameters/exercise3.js
@@ -1,5 +1,8 @@
 // Write your function here
+function createGreeting(name) {
+    return `Hello, my name is ${name}`;
+}
 
-var greeting = createGreeting("Daniel");
+const greeting = createGreeting("Daniel");
 
 console.log(greeting);
diff --git a/exercises/K-functions-parameters/exercise4.js b/exercises/K-functions-parameters/exercise4.js
index 7ab44589e..4d7706573 100644
--- a/exercises/K-functions-parameters/exercise4.js
+++ b/exercises/K-functions-parameters/exercise4.js
@@ -1,5 +1,9 @@
 // Declare your function first
+function add(num1, num2) {
+    return num1 + num2;
+}
 
 // Call the function and assign to a variable `sum`
+const 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..01bd81eb5 100644
--- a/exercises/K-functions-parameters/exercise5.js
+++ b/exercises/K-functions-parameters/exercise5.js
@@ -1,4 +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);
 
diff --git a/exercises/L-functions-nested/exercise.js b/exercises/L-functions-nested/exercise.js
index a5d377442..4d16d043e 100644
--- a/exercises/L-functions-nested/exercise.js
+++ b/exercises/L-functions-nested/exercise.js
@@ -1,5 +1,43 @@
-var mentor1 = "Daniel";
-var mentor2 = "Irina";
-var mentor3 = "Mimi";
-var mentor4 = "Rob";
-var mentor5 = "Yohannes";
+const mentor1 = "Daniel";
+const mentor2 = "Irina";
+const mentor3 = "Mimi";
+const mentor4 = "Rob";
+const mentor5 = "Yohannes";
+
+
+function createShoutyGreeting (name) {
+    name = name.toUpperCase();
+    console.log(`HELLO ${name}`);
+}
+
+createShoutyGreeting(mentor1);
+createShoutyGreeting(mentor2);
+createShoutyGreeting(mentor3);
+createShoutyGreeting(mentor4);
+createShoutyGreeting(mentor5);
+
+
+
+
+// Another way of doing the exercise
+/*
+function nameInUpperCase(name) {
+    return name.toUpperCase();
+}
+
+function createShoutyGreeting() {
+    const name1 = nameInUpperCase(mentor1);
+    const name2 = nameInUpperCase(mentor2);
+    const name3 = nameInUpperCase(mentor3);
+    const name4 = nameInUpperCase(mentor4);
+    const name5 = nameInUpperCase(mentor5);
+    console.log(`HELLO ${name1}`);
+    console.log(`HELLO ${name2}`);
+    console.log(`HELLO ${name3}`);
+    console.log(`HELLO ${name4}`);
+    console.log(`HELLO ${name5}`);
+}
+
+createShoutyGreeting();
+*/
+
diff --git a/extra/1-currency-conversion.js b/extra/1-currency-conversion.js
index 07391e15f..90bad306b 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(pound) {
+  const usd = pound * 1.4;
+  return usd;
+}
 
 /*
   CURRENCY FORMATTING
@@ -15,7 +18,11 @@ 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(pound) {
+  const afterFee = pound * 0.99; 
+  const brl = afterFee * 5.7;
+  return parseFloat(brl.toFixed(2));
+}
 
 /* ======= TESTS - DO NOT MODIFY ===== 
 There are some Tests in this file that will help you work out if your code is working.
@@ -37,5 +44,5 @@ test("convertToBRL function works for £30", () => {
 });
 
 test("convertToBRL function works for £0.99", () => {
-  expect(convertToBRL(1.5)).toEqual(8.46);
+  expect(convertToBRL(1.50)).toEqual(8.46);
 });
diff --git a/extra/2-piping.js b/extra/2-piping.js
index 9c8ebc76a..521036b12 100644
--- a/extra/2-piping.js
+++ b/extra/2-piping.js
@@ -16,26 +16,30 @@
   the final result to the variable goodCode
 */
 
-function add() {
-
+function add(num1, num2) {
+  return num1 + num2;
 }
 
-function multiply() {
-
+function multiply(num1, num2) {
+  return num1 * num2;
 }
 
-function format() {
-
+function format(num) {
+  return `£${num}`;
 }
 
 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));  //This code is not easy to read and understand
 
 /* BETTER PRACTICE */
 
-let goodCode =
+const addedNumber = add(startingValue, 10);
+const multiplied = multiply(addedNumber, 2);
+const formatted = format(multiplied);
+
+let goodCode = formatted;
 
 /* ======= 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/3-magic-8-ball.js b/extra/3-magic-8-ball.js
index 7626877e7..0e9692f7c 100644
--- a/extra/3-magic-8-ball.js
+++ b/extra/3-magic-8-ball.js
@@ -43,12 +43,78 @@
     Very doubtful.
 */
 
+let question;
+
+const answers = [
+  //Very positive
+  "It is certain.",
+  "It is decidedly so.",
+  "Without a doubt.",
+  "Yes - definitely.",
+  "You may rely on it.",
+  //Positive
+  "As I see it, yes.",
+  "Most likely.",
+  "Outlook good.",
+  "Yes.",
+  "Signs point to yes.",
+  //Negative
+  "Reply hazy, try again.",
+  "Ask again later.",
+  "Better not tell you now.",
+  "Cannot predict now.",
+  "Concentrate and ask again.",
+  //Very Negative
+  "Don't count on it.",
+  "My reply is no.",
+  "My sources say no.",
+  "Outlook not so good.",
+  "Very doubtful.",
+];
+
+const veryPositive = [
+  "It is certain.",
+  "It is decidedly so.",
+  "Without a doubt.",
+  "Yes - definitely.",
+  "You may rely on it.",
+];
+
+const positive = [
+  "As I see it, yes.",
+  "Most likely.",
+  "Outlook good.",
+  "Yes.",
+  "Signs point to yes.",
+];
+
+const negative = [
+  "Reply hazy, try again.",
+  "Ask again later.",
+  "Better not tell you now.",
+  "Cannot predict now.",
+  "Concentrate and ask again.",
+];
+
+const veryNegative = [
+  "Don't count on it.",
+  "My reply is no.",
+  "My sources say no.",
+  "Outlook not so good.",
+  "Very doubtful.",
+];
+
 // This should log "The ball has shaken!"
 // and return the answer.
 function shakeBall() {
   //Write your code in here
+  console.log("The ball has shaken!");
+  const answer = answers[Math.floor(Math.random() * answers.length)];
+  return answer;
 }
 
+shakeBall();
+
 /* 
   This function should say whether the answer it is given is
     - very positive
@@ -60,8 +126,46 @@ function shakeBall() {
 */
 function checkAnswer(answer) {
   //Write your code in here
+  let index;
+  for (let i = 0; i < answers.length; i++) {
+    if (answer === answers[i]) {
+      index = i;
+    } else {
+      console.log("Answer is not recognized. Please input an answer in answers array.");
+    }
+  }
+  if (index < 5) {
+    return "very positive";
+  } else if (index >= 5 && index < 10) {
+    return "positive";
+  } else if (index >= 10 && index < 15) {
+    return "negative";
+  } else {
+    return "very negative";
+  }
+}
+
+checkAnswer(shakeBall());
+
+/* Another way of doing the exercise; used arrays for "very positive", "positive", "negative", and "very negative" answers, and then used includes method in checkAnswer function 
+
+function checkAnswer(answer) {
+  //Write your code in here
+  if (veryPositive.includes(answer)) {
+    console.log(`very positive`);
+  } else if (positive.includes(answer)) {
+    console.log(`positive`);
+  } else if (negative.includes(answer)) {
+    console.log(`negative`);
+  } else if (veryNegative.includes(answer)) {
+    console.log(`very negative`);
+  } else {
+    console.log(`something unexpected happened`);
+  }
 }
 
+*/ 
+
 /* 
 ==================================
 ======= TESTS - DO NOT MODIFY =====
diff --git a/mandatory/1-syntax-errors.js b/mandatory/1-syntax-errors.js
index a10cc9ac2..67626215a 100644
--- a/mandatory/1-syntax-errors.js
+++ b/mandatory/1-syntax-errors.js
@@ -1,16 +1,18 @@
 // 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;
+  const 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..8d7956ad7 100644
--- a/mandatory/2-logic-error.js
+++ b/mandatory/2-logic-error.js
@@ -1,16 +1,15 @@
 // 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;
+  return a * b * c;
 }
 
 /* 
@@ -34,12 +33,12 @@ test("trimWord doesn't remove whitespace in the middle of the string", () => {
   );
 });
 
-test("getStringLength returns the length of a word", () => {
-  expect(getStringLength("Turtles")).toEqual(7);
+test("getWordLength returns the length of a word", () => {
+  expect(getWordLength("Turtles")).toEqual(7);
 });
 
-test("getStringLength returns the length of a sentence", () => {
-  expect(getStringLength("A wild sentence appeared!")).toEqual(25);
+test("getWordLength returns the length of a sentence", () => {
+  expect(getWordLength("A wild sentence appeared!")).toEqual(25);
 });
 
 test("multiply multiplies numbers", () => {
diff --git a/mandatory/3-function-output.js b/mandatory/3-function-output.js
index 5a953ba60..6f7158f4e 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!
+/*Math.random() function gives a random number between 0 and 1, get the number with the function and multiply it with 10 */
 function getRandomNumber() {
   return Math.random() * 10;
 }
 
 // Add comments to explain what this function does. You're meant to use Google!
+/* concat() method concatenates the input given, such as string or array; in this example it concatenates word2 to the end of word1 */  
 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..553f98e15 100644
--- a/mandatory/4-tax.js
+++ b/mandatory/4-tax.js
@@ -5,7 +5,11 @@
   Sales tax is 20% of the price of the product.
 */
 
-function calculateSalesTax() {}
+function calculateSalesTax(priceProduct) {
+  const tax = priceProduct * 0.2;
+  const priceTotal = priceProduct + tax;
+  return priceTotal;
+}
 
 /*
   CURRENCY FORMATTING
@@ -17,7 +21,11 @@ function calculateSalesTax() {}
   Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
 */
 
-function addTaxAndFormatCurrency() {}
+function addTaxAndFormatCurrency(priceProduct) {
+  const priceTotal = calculateSalesTax(priceProduct);
+  const format = priceTotal.toFixed(2);
+  return `£${format}`;
+}
 
 /* 
 ===================================================
diff --git a/package.json b/package.json
index 58555936d..778df9683 100644
--- a/package.json
+++ b/package.json
@@ -14,7 +14,9 @@
     "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": {