diff --git a/exercises/B-hello-world/exercise.js b/exercises/B-hello-world/exercise.js
index b179ee953..745f0a5a0 100644
--- a/exercises/B-hello-world/exercise.js
+++ b/exercises/B-hello-world/exercise.js
@@ -1 +1,6 @@
 console.log("Hello world");
+
+console.log (12345);
+console.log ("Hello World I just started learning Jvascript");
+
+
diff --git a/exercises/C-variables/exercise.js b/exercises/C-variables/exercise.js
index a6bbb9786..0fdd177dc 100644
--- a/exercises/C-variables/exercise.js
+++ b/exercises/C-variables/exercise.js
@@ -1,3 +1,6 @@
 // Start by creating a variable `greeting`
+let 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..d4da48084 100644
--- a/exercises/D-strings/exercise.js
+++ b/exercises/D-strings/exercise.js
@@ -1,3 +1,7 @@
 // Start by creating a variable `message`
+let message = "This is a string in Javascript";
+let 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..743f1b6a1 100644
--- a/exercises/E-strings-concatenation/exercise.js
+++ b/exercises/E-strings-concatenation/exercise.js
@@ -1,3 +1,8 @@
 // Start by creating a variable `message`
+var greetingStart = "Hello, my name is ";
+var name = "Karleen";
+var greetingEnd = ", I'm glad you visited."
 
-console.log(message);
+var greeting = greetingStart + name + greetingEnd;
+
+console.log(greeting);
diff --git a/exercises/I-floats/exercise.js b/exercises/I-floats/exercise.js
index a5bbcd852..800d9eee3 100644
--- a/exercises/I-floats/exercise.js
+++ b/exercises/I-floats/exercise.js
@@ -1,2 +1,15 @@
 var numberOfStudents = 15;
 var numberOfMentors = 8;
+
+const amtOfTrainees = "Number of trainees: ";
+const numberOfTrainees = 36;
+
+console.log (amtOfTrainees + numberOfTrainees);
+
+const amtOfMentors = "Number of mentors: ";
+const numberOfMentors = 10;
+
+console.log (amtOfMentors + numberOfMentors);
+
+const sum = 36 + 10;
+console.log ("Total number of trainees and mentors: " + sum);
\ No newline at end of file
diff --git a/exercises/J-functions/exercise.js b/exercises/J-functions/exercise.js
index 0ae5850e5..edab3cb27 100644
--- a/exercises/J-functions/exercise.js
+++ b/exercises/J-functions/exercise.js
@@ -1,7 +1,13 @@
-function halve(number) {
-  // complete the function here
+
+function increaseByHalf(number) {
+  return number / 2 + number
 }
 
-var result = halve(12);
+var result = increaseByHalf(400);
+console.log(result);
 
+var result = increaseByHalf(1000);
 console.log(result);
+
+var result = increaseByHalf(8500);
+console.log(result);
\ No newline at end of file
diff --git a/extra/1-currency-conversion.js b/extra/1-currency-conversion.js
index 75b3c6aab..8247214b9 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(number) {
+  return number * 1.4;
+}
+
+console.log(convertToUSD(32));
+console.log(convertToUSD(50));
 
 /*
   CURRENCY CONVERSION
@@ -15,7 +20,13 @@ 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(a) {
+  a = (a * (99 / 100 * 5.7)).toFixed(2);
+  return +a;
+}
+
+console.log(convertToBRL(30));
+console.log(convertToBRL(1.50));
 
 /* ======= 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..38859c5a9 100644
--- a/extra/2-piping.js
+++ b/extra/2-piping.js
@@ -16,26 +16,41 @@
   the final result to the variable goodCode
 */
 
-function add() {
-
+function add(a,b) {
+  return (a + b).toFixed(1);
 }
 
-function multiply() {
+console.log(add(1,3));
+console.log(add(2.4,5))
 
+function multiply(c,d) {
+  return c * d;
 }
 
-function format() {
+console.log(multiply(2,3))
 
+function format(str) {
+  return "£" + str;
 }
 
-const startingValue = 2;
+console.log(format(16));
+console.log(format(10.1));
 
+const startingValue = 2; 
 // Why can this code be seen as bad practice? Comment your answer.
-let badCode =
+//It is bad practice because the code is difficult to understand and read.
+let badCode = format(multiply(add(startingValue,10),2));
+
+console.log(badCode);
+
+
 
 /* BETTER PRACTICE */
+let first = startingValue + 10;
+let second = first * 2;
+let goodCode = format(second);
 
-let goodCode =
+console.log(goodCode);
 
 /* ======= 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..d9dcc6ab7 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;
-
-  return "The total is total";
+  const total = a + b;
+  return "The total is " + total;
 }
 
 /* 
diff --git a/mandatory/2-logic-error.js b/mandatory/2-logic-error.js
index 9cca7603b..a7235f9bb 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 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..a22f84a84 100644
--- a/mandatory/3-function-output.js
+++ b/mandatory/3-function-output.js
@@ -2,13 +2,16 @@
 function getRandomNumber() {
   return Math.random() * 10;
 }
+// The Math.random method returns a floating-point, pseudo-random number that's greater than or equal to 0 and less than 1.
 
 // Add comments to explain what this function does. You're meant to use Google!
 function combine2Words(word1, word2) {
   return word1.concat(word2);
 }
+//The .concat method joins two or more strings.
 
 function concatenate(firstWord, secondWord, thirdWord) {
+  return firstWord.concat(" ",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.
 }
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index ba77c7ae2..7e05a2df2 100644
--- a/mandatory/4-tax.js
+++ b/mandatory/4-tax.js
@@ -5,8 +5,13 @@
   Sales tax is 20% of the price of the product.
 */
 
-function calculateSalesTax() {}
-
+function calculateSalesTax(a) {
+  
+  return (20 / 100 * a) + a;
+}
+console.log(calculateSalesTax(15));
+console.log(calculateSalesTax(17.50));
+console.log(calculateSalesTax(34));
 /*
   CURRENCY FORMATTING
   ===================
@@ -17,7 +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(b) {
+  return "£" + ((20 / 100 * b) + b).toFixed(2);
+}
+console.log(addTaxAndFormatCurrency(15));
+console.log(addTaxAndFormatCurrency(17.50));
+console.log(addTaxAndFormatCurrency(34));
 
 /* 
 ===================================================