diff --git a/exercises/C-variables/exercise.js b/exercises/C-variables/exercise.js
index a6bbb9786..eeab4e8a9 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..042c5b7f4 100644
--- a/exercises/D-strings/exercise.js
+++ b/exercises/D-strings/exercise.js
@@ -1,3 +1,6 @@
 // Start by creating a variable `message`
+let message = "This is a bird string";
+let messageType = typeof message;
 
+console.log(messageType);
 console.log(message);
diff --git a/exercises/E-strings-concatenation/exercise.js b/exercises/E-strings-concatenation/exercise.js
index 2cffa6a81..a6754ba17 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`
+let greetingStart = "Hello, my name is ";
+let name = "Alessandra";
+
+let greeting = greetingStart + name;
+
+console.log(greeting);
 
-console.log(message);
diff --git a/exercises/F-strings-methods/exercise.js b/exercises/F-strings-methods/exercise.js
index 2cffa6a81..5214932f6 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 = "Alessandra";
+let nameLength = name.length;
+
+console.log(nameLength);
 
-console.log(message);
diff --git a/exercises/F-strings-methods/exercise2.js b/exercises/F-strings-methods/exercise2.js
index b4b46943d..6a2cf33ac 100644
--- a/exercises/F-strings-methods/exercise2.js
+++ b/exercises/F-strings-methods/exercise2.js
@@ -1,3 +1,4 @@
-const name = " Daniel  ";
+let name = "Alessandra";
+let nameLowerCase = name.toLowerCase();
 
-console.log(message);
+console.log(nameLowerCase);
diff --git a/exercises/G-numbers/README.md b/exercises/G-numbers/README.md
index 76a79dab2..75136adf1 100644
--- a/exercises/G-numbers/README.md
+++ b/exercises/G-numbers/README.md
@@ -6,7 +6,7 @@ Unlike strings, numbers do not need to be wrapped in quotes.
 var age = 30;
 ```
 
-You can use mathematical operators to caclulate numbers:
+You can use mathematical operators to calculate numbers:
 
 ```js
 var sum = 10 + 2; // 12
@@ -25,5 +25,5 @@ var difference = 10 - 2; // 8
 ```
 Number of students: 15
 Number of mentors: 8
-Total numnber of students and mentors: 23
+Total number of students and mentors: 23
 ```
diff --git a/exercises/G-numbers/exercise.js b/exercises/G-numbers/exercise.js
index 49e7bc00b..8a14f2bfa 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;
+let numberOfMentors = 8;
+
+let sum = numberOfMentors+numberOfStudents
+
+console.log(sum)
\ No newline at end of file
diff --git a/exercises/I-floats/exercise.js b/exercises/I-floats/exercise.js
index a5bbcd852..d343104de 100644
--- a/exercises/I-floats/exercise.js
+++ b/exercises/I-floats/exercise.js
@@ -1,2 +1,11 @@
 var numberOfStudents = 15;
 var numberOfMentors = 8;
+
+let percentageOfStudents = ((15 / 23) *100)
+//console.log(percentageOfTrainees)
+console.log(`Percentage of students: ${Math.round(percentageOfStudents)}%`);
+
+let percentageOfMentors = ((8 / 23) * 100)
+//console.log(percentageOfMentors)
+console.log(`Percentage of mentors: ${Math.round(percentageOfMentors)}%`);
+
diff --git a/exercises/J-functions/exercise.js b/exercises/J-functions/exercise.js
index 0ae5850e5..dde21a2f2 100644
--- a/exercises/J-functions/exercise.js
+++ b/exercises/J-functions/exercise.js
@@ -1,7 +1,14 @@
 function halve(number) {
+  return number/2;
   // complete the function here
 }
+var result = halve(88);
+console.log(result);
 
-var result = halve(12);
-
+function halve(number) {
+  return number / 2;
+}
+var result = halve(1200);
 console.log(result);
+//code only works with var??
+
diff --git a/exercises/J-functions/exercise2.js b/exercises/J-functions/exercise2.js
index 82ef5e780..88a02877b 100644
--- a/exercises/J-functions/exercise2.js
+++ b/exercises/J-functions/exercise2.js
@@ -1,7 +1,22 @@
 function triple(number) {
   // complete function here
+  return number*3;
 }
 
 var result = triple(12);
+console.log(result);
 
+function triple(number) {
+  return number*3;
+}
+
+var result = triple(1200);
 console.log(result);
+
+
+function triple(number) {
+  return number*3;
+}
+
+var result = triple(550);
+console.log(result);
\ No newline at end of file
diff --git a/exercises/K-functions-parameters/exercise.js b/exercises/K-functions-parameters/exercise.js
index 8d5db5e69..63ec7a93a 100644
--- a/exercises/K-functions-parameters/exercise.js
+++ b/exercises/K-functions-parameters/exercise.js
@@ -1,5 +1,6 @@
 // Complete the function so that it takes input parameters
-function multiply() {
+function multiply(num1, num2) {
+return num1 * num2;
   // Calculate the result of the function and return it
 }
 
@@ -7,3 +8,4 @@ function multiply() {
 var 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..35dae2fd6 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);
 
 console.log(result);
+
+
diff --git a/exercises/K-functions-parameters/exercise3.js b/exercises/K-functions-parameters/exercise3.js
index 537e9f4ec..60578e941 100644
--- a/exercises/K-functions-parameters/exercise3.js
+++ b/exercises/K-functions-parameters/exercise3.js
@@ -1,5 +1,7 @@
 // Write your function here
+function createGreeting(myName) {
+    return (`Hello, my name is ` + myName);
+}
 
 var greeting = createGreeting("Daniel");
-
-console.log(greeting);
+console.log(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..04691dec2 100644
--- a/exercises/K-functions-parameters/exercise4.js
+++ b/exercises/K-functions-parameters/exercise4.js
@@ -1,5 +1,10 @@
 // Declare your function first
-
+function addTogether(a, b){
+return (a + b);
+}
 // Call the function and assign to a variable `sum`
-
+let sum = addTogether(13, 124);
 console.log(sum);
+
+
+
diff --git a/exercises/K-functions-parameters/exercise5.js b/exercises/K-functions-parameters/exercise5.js
index 7c5bcd605..9965aad5b 100644
--- a/exercises/K-functions-parameters/exercise5.js
+++ b/exercises/K-functions-parameters/exercise5.js
@@ -1,5 +1,11 @@
 // 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);
+
+
+
+//Hello, my name is Daniel and I'm 30 years old
\ No newline at end of file
diff --git a/exercises/L-functions-nested/exercise.js b/exercises/L-functions-nested/exercise.js
index a5d377442..77787e16e 100644
--- a/exercises/L-functions-nested/exercise.js
+++ b/exercises/L-functions-nested/exercise.js
@@ -1,5 +1,19 @@
-var mentor1 = "Daniel";
-var mentor2 = "Irina";
-var mentor3 = "Mimi";
-var mentor4 = "Rob";
-var mentor5 = "Yohannes";
+
+function greetings(mentor) {
+// let mentor1 = "Daniel";
+// let mentor2 = "Irina";
+// let mentor3 = "Mimi";
+// let mentor4 = "Rob";
+// let mentor5 = "Yohannes";
+let result = `Hello ${mentor}`
+console.log(result.toUpperCase())
+}
+
+greetings("Daniel");
+greetings("Irina");
+greetings("Mimi");
+greetings("Rob");
+greetings("Yohannes");
+   
+    
+    
diff --git a/mandatory/1-syntax-errors.js b/mandatory/1-syntax-errors.js
index a10cc9ac2..91bb6556b 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..49fceab19 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..1917ad2ff 100644
--- a/mandatory/3-function-output.js
+++ b/mandatory/3-function-output.js
@@ -1,18 +1,24 @@
 // Add comments to explain what this function does. You're meant to use Google!
 function getRandomNumber() {
   return Math.random() * 10;
+  //This function returns a random number between 0 and 9.
 }
 
 // Add comments to explain what this function does. You're meant to use Google!
 function combine2Words(word1, word2) {
   return word1.concat(word2);
+  //This function joins two words together. 
 }
 
+
 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.concat(' ', secondWord, ' ', thirdWord);
+  return firstWord.concat(" ", secondWord, " ", thirdWord);
 }
 
+
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index ba77c7ae2..e2adb054c 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(originalPrice) {
+  const taxRate = 20;
+  const amountOfTax = originalPrice * (taxRate / 100);
+  return originalPrice + amountOfTax;
+}
 
 /*
   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(price) {
+  const priceWithTax = calculateSalesTax(price);
+  const formattedPrice = '£' + priceWithTax.toFixed(2);
+  return formattedPrice;
+}
 
 /* 
 ===================================================