diff --git a/exercises/B-hello-world/exercise.js b/exercises/B-hello-world/exercise.js
index b179ee953..1c960d355 100644
--- a/exercises/B-hello-world/exercise.js
+++ b/exercises/B-hello-world/exercise.js
@@ -1 +1,4 @@
-console.log("Hello world");
+console.log("Hello World. I just started learning JavaScript!.");
+console.log("I like playing piano.");
+console.log(2 + 2);
+
diff --git a/exercises/C-variables/exercise.js b/exercises/C-variables/exercise.js
index a6bbb9786..7a449fb32 100644
--- a/exercises/C-variables/exercise.js
+++ b/exercises/C-variables/exercise.js
@@ -1,3 +1,7 @@
 // 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..c0610b025 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";
+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..e447926f3 100644
--- a/exercises/E-strings-concatenation/exercise.js
+++ b/exercises/E-strings-concatenation/exercise.js
@@ -1,3 +1,6 @@
 // Start by creating a variable `message`
+let greetingStart = " Hello my name is ";
+let name = "Ntshumayelo";
 
-console.log(message);
+let greeting = greetingStart + name;
+console.log(greeting);
diff --git a/exercises/F-strings-methods/exercise.js b/exercises/F-strings-methods/exercise.js
index 2cffa6a81..ce7a8441c 100644
--- a/exercises/F-strings-methods/exercise.js
+++ b/exercises/F-strings-methods/exercise.js
@@ -1,3 +1,6 @@
 // Start by creating a variable `message`
+let name = "Ntshumayelo";
+let message = "My name is Ntshumayelo";
 
-console.log(message);
+console.log(nameLength);
+ 
\ No newline at end of file
diff --git a/exercises/F-strings-methods/exercise2.js b/exercises/F-strings-methods/exercise2.js
index b4b46943d..2fda01a20 100644
--- a/exercises/F-strings-methods/exercise2.js
+++ b/exercises/F-strings-methods/exercise2.js
@@ -1,3 +1,5 @@
-const name = " Daniel  ";
-
+const name = "Daniel";
+let lengthName = name.length
+let message = "my name is " + name.trim() + " and my name is " + lengthName + " characters long";
 console.log(message);
+//console.log(name.trim); 
diff --git a/exercises/G-numbers/exercise.js b/exercises/G-numbers/exercise.js
index 49e7bc00b..b681054ba 100644
--- a/exercises/G-numbers/exercise.js
+++ b/exercises/G-numbers/exercise.js
@@ -1 +1,13 @@
 // Start by creating a variables `numberOfStudents` and `numberOfMentors`
+let numberOfStudents = 15 
+let numberOfMentors = 8
+let totalNumberOfStudentsMentors = numberOfStudents + numberOfMentors;
+
+let percentageOfStudents = numberOfStudents * 100 /totalNumberOfStudentsMentors;
+percentageOfStudents = Math.round(percentageOfStudents); 
+console.log("Percentage of Students: " + percentageOfStudents + "%");
+
+
+let percentageOfMentors = numberOfMentors * 100 /totalNumberOfStudentsMentors;
+percentageOfMentors = Math.round(percentageOfMentors); 
+console.log("Percentage of Mentors: " + percentageOfMentors + "%");
\ No newline at end of file
diff --git a/exercises/J-functions/exercise.js b/exercises/J-functions/exercise.js
index 0ae5850e5..175c40aff 100644
--- a/exercises/J-functions/exercise.js
+++ b/exercises/J-functions/exercise.js
@@ -1,7 +1,9 @@
 function halve(number) {
+  let result = number / 2;
+  return result;
   // complete the function here
 }
 
-var result = halve(12);
+let result = halve(12);
 
 console.log(result);
diff --git a/exercises/J-functions/exercise2.js b/exercises/J-functions/exercise2.js
index 82ef5e780..75d1c2f90 100644
--- a/exercises/J-functions/exercise2.js
+++ b/exercises/J-functions/exercise2.js
@@ -1,4 +1,5 @@
 function triple(number) {
+  return number * 3;
   // complete function here
 }
 
diff --git a/exercises/K-functions-parameters/exercise.js b/exercises/K-functions-parameters/exercise.js
index 8d5db5e69..89a6715df 100644
--- a/exercises/K-functions-parameters/exercise.js
+++ b/exercises/K-functions-parameters/exercise.js
@@ -1,5 +1,7 @@
 // Complete the function so that it takes input parameters
-function multiply() {
+function multiply(num1, num2) {
+ let result = num1 * num2; 
+ return result;
   // Calculate the result of the function and return it
 }
 
diff --git a/exercises/K-functions-parameters/exercise2.js b/exercises/K-functions-parameters/exercise2.js
index db7a8904b..4d84416f3 100644
--- a/exercises/K-functions-parameters/exercise2.js
+++ b/exercises/K-functions-parameters/exercise2.js
@@ -1,5 +1,8 @@
 // Declare your function first
-
+function divide(num1, num2){
+let result = num1 / num2;
+return result;
+}
 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..a6ac13c76 100644
--- a/exercises/K-functions-parameters/exercise3.js
+++ b/exercises/K-functions-parameters/exercise3.js
@@ -1,5 +1,8 @@
 // Write your function here
-
-var greeting = createGreeting("Daniel");
+function createGreeting(name){
+let greeting = "Hello, My name is ${name}"
+return greeting;
+}
+let greeting = createGreeting("Daniel");
 
 console.log(greeting);
diff --git a/exercises/K-functions-parameters/exercise4.js b/exercises/K-functions-parameters/exercise4.js
index 7ab44589e..2fddf9390 100644
--- a/exercises/K-functions-parameters/exercise4.js
+++ b/exercises/K-functions-parameters/exercise4.js
@@ -1,5 +1,8 @@
 // Declare your function first
-
+function sumNumbers(num1, num2){
+    let result = num1 + num2;
+    return result;
+}
 // Call the function and assign to a variable `sum`
-
+let sum = sumNumbers(13,124)
 console.log(sum);
diff --git a/exercises/K-functions-parameters/exercise5.js b/exercises/K-functions-parameters/exercise5.js
index 7c5bcd605..9256e0619 100644
--- a/exercises/K-functions-parameters/exercise5.js
+++ b/exercises/K-functions-parameters/exercise5.js
@@ -1,5 +1,8 @@
 // Declare your function here
-
+function createLongGreeting(name, age){
+    let greeting = "Hello, my name is ${name} and I'm ${age} old"
+    return greeting;
+}
 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..edeae7ffd 100644
--- a/exercises/L-functions-nested/README.md
+++ b/exercises/L-functions-nested/README.md
@@ -28,7 +28,7 @@ function createCreeting(name, age) {
 ```
 HELLO DANIEL
 HELLO IRINA
-HELLO MIMI
+HELLO MIMIv  
 HELLO ROB
 HELLO YOHANNES
 ```
diff --git a/exercises/L-functions-nested/exercise.js b/exercises/L-functions-nested/exercise.js
index a5d377442..f4096e7a5 100644
--- a/exercises/L-functions-nested/exercise.js
+++ b/exercises/L-functions-nested/exercise.js
@@ -3,3 +3,22 @@ var mentor2 = "Irina";
 var mentor3 = "Mimi";
 var mentor4 = "Rob";
 var mentor5 = "Yohannes";
+
+let mentor1 = "Daniel";
+let mentor2 = "Irina";
+let mentor3 = "Mimi";
+let mentor4 = "Rob";
+let mentor5 = "Yohannes";
+
+function spellName(name) {
+    return name.toUpperCase();
+  }
+function shoutyGreeting(name){
+    let message = 'HELLO '+ spellName(name);
+    return message
+};
+console.log(shoutyGreeting(mentor1));
+console.log(shoutyGreeting(mentor2));
+console.log(shoutyGreeting(mentor3));
+console.log(shoutyGreeting(mentor4));
+console.log(shoutyGreeting(mentor5));
\ No newline at end of file
diff --git a/mandatory/1-syntax-errors.js b/mandatory/1-syntax-errors.js
index a10cc9ac2..2e1fd877c 100644
--- a/mandatory/1-syntax-errors.js
+++ b/mandatory/1-syntax-errors.js
@@ -1,16 +1,17 @@
 // 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 9cca7603b..9d1dc284f 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..671f1c73c 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!
+//returns a random number between 0 (inclusive) and 1 (exclusive) and multiplies with 10
 function getRandomNumber() {
   return Math.random() * 10;
 }
 
 // Add comments to explain what this function does. You're meant to use Google!
+// This function combines typed array with the new array.
 function combine2Words(word1, word2) {
   return word1.concat(word2);
 }
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index ba77c7ae2..779402efb 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(priceOfProduct) {
+  let percentageOfProduct = (priceOfProduct) * 0.2;
+  return percentageOfProduct + (priceOfProduct);
+}
 
 /*
   CURRENCY FORMATTING
@@ -17,7 +20,10 @@ function calculateSalesTax() {}
   Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
 */
 
-function addTaxAndFormatCurrency() {}
+function addTaxAndFormatCurrency(num) {
+let priceWithSalesTax = calculateSalesTax(num);
+return "£" + priceWithSalesTax.toFixed(2);
+}
 
 /* 
 ===================================================