diff --git a/exercises/B-hello-world/exercise.js b/exercises/B-hello-world/exercise.js
index b179ee953..ef14d9328 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 World");
+console.log(5);
+
+// When I console.log several things at once, I get a list of answers.
+
+// When I get rid of quotes,I get a syntax error.
+console.log(Hello World.I just started learning JavaScript!);
+
+console.log("Hello World. I just started learning JavaScript!");
+
+// A number without quotes.
+console.log(205);
\ No newline at end of file
diff --git a/exercises/C-variables/exercise.js b/exercises/C-variables/exercise.js
index a6bbb9786..c8382f8d2 100644
--- a/exercises/C-variables/exercise.js
+++ b/exercises/C-variables/exercise.js
@@ -1,3 +1,12 @@
-// Start by creating a variable `greeting`
+var approach = "greeting";// Start by creating a variable `greeting`
+
+let greeting = "Hello World"
+console.log(greeting);
+
+var approach = "greeting";// Start by creating a variable `greeting`
+
+console.log(greeting);
+
+var approach = "greeting";// Start by creating a variable `greeting`
 
 console.log(greeting);
diff --git a/exercises/D-strings/exercise.js b/exercises/D-strings/exercise.js
index 2cffa6a81..9f9b5484f 100644
--- a/exercises/D-strings/exercise.js
+++ b/exercises/D-strings/exercise.js
@@ -1,3 +1,13 @@
-// Start by creating a variable `message`
+const message = "This is a String";
+const messageType = typeof message;
+
 
 console.log(message);
+console.log(messageType);
+
+// My copy
+const myText = "This is a String of Douglas";
+const usingTypeof = typeof myText;
+
+console.log(myText);
+console.log(usingTypeof);
\ No newline at end of file
diff --git a/exercises/E-strings-concatenation/exercise.js b/exercises/E-strings-concatenation/exercise.js
index 2cffa6a81..fd8cae8ac 100644
--- a/exercises/E-strings-concatenation/exercise.js
+++ b/exercises/E-strings-concatenation/exercise.js
@@ -1,3 +1,13 @@
-// Start by creating a variable `message`
+// const introduction = "Hello my name is";
+// const name = "  Abdulqadir";
 
-console.log(message);
+// console.log(introduction);
+// console.log(name);
+
+// My copy
+let standardIntro = "Hello, my first name is";
+let yourName = " Douglas.";
+
+let greeting = standardIntro + yourName;
+
+console.log(greeting);
\ No newline at end of file
diff --git a/exercises/F-strings-methods/exercise.js b/exercises/F-strings-methods/exercise.js
index 2cffa6a81..c91e33d42 100644
--- a/exercises/F-strings-methods/exercise.js
+++ b/exercises/F-strings-methods/exercise.js
@@ -1,3 +1,11 @@
-// Start by creating a variable `message`
+// let name = "Abdulqadir";
+// let nameLength = name.length;
 
-console.log(message);
+// console.log(`My name is ${name} and my name is ${name.length} characters long`);
+
+
+let myName = "Douglas Trainee";
+let myNameLength = myName.length;
+
+// With interpolation, I don't need to create another variable for the greeting text.
+console.log(`My name is ${myName} and my name is ${myNameLength} characters long`);
\ No newline at end of file
diff --git a/exercises/F-strings-methods/exercise2.js b/exercises/F-strings-methods/exercise2.js
index b4b46943d..635ede2ff 100644
--- a/exercises/F-strings-methods/exercise2.js
+++ b/exercises/F-strings-methods/exercise2.js
@@ -1,3 +1,17 @@
-const name = " Daniel  ";
+let name  = "Abdulqadir";
+let addTrim = name.trim();
+let newNameLength = addTrim.length;
 
-console.log(message);
+console.log(`my name is ${addTrim} and my name is ${newNameLength} characters long`);
+
+let myName = "  Douglas Trainee  ";
+let myNameLength = myName.length;
+
+let myNameTrim = myName.trim();
+let myNewNameLength = myNameTrim.length;
+
+// 19 characters for myName
+console.log(`My name is ${myName} and my name is ${myNameLength} characters long`);
+
+// The whitespaces are removed: 15 characters for myName
+console.log(`My name is ${myNameTrim} and my name is ${myNewNameLength} characters long`);
\ No newline at end of file
diff --git a/exercises/G-numbers/exercise.js b/exercises/G-numbers/exercise.js
index 49e7bc00b..b91af39eb 100644
--- a/exercises/G-numbers/exercise.js
+++ b/exercises/G-numbers/exercise.js
@@ -1 +1,17 @@
 // Start by creating a variables `numberOfStudents` and `numberOfMentors`
+// let numberOfStudents = 15;
+// let numberOfMentors = 3;
+// let total = numberOfStudents + numberOfMentors;
+
+// console.log(`number of students: ${numberOfStudents}`);
+// console.log(`number of mentors: ${numberOfMentors}` );
+// console.log(`total number of students and mentors: ${total}`);
+
+// My copy.
+let numberOfStudents = 30;
+let numberOfMentors = 10;
+let total = numberOfStudents + numberOfMentors;
+
+console.log(`Number of students: ${numberOfStudents}`);
+console.log(`Number of mentors: ${numberOfMentors}`);
+console.log(`Total number of students and mentors: ${total}`);
\ No newline at end of file
diff --git a/exercises/I-floats/exercise.js b/exercises/I-floats/exercise.js
index a5bbcd852..d95575386 100644
--- a/exercises/I-floats/exercise.js
+++ b/exercises/I-floats/exercise.js
@@ -1,2 +1,23 @@
-var numberOfStudents = 15;
-var numberOfMentors = 8;
+// var numberOfStudents = 15;
+// var numberOfMentors = 8;
+// var total = numberOfStudents + numberOfMentors;
+
+// var convertStudent = numberOfStudents/total*100;
+// var convertMentors = numberOfMentors/total*100;
+
+// var percentageOfStudents = Math.round(convertStudent);
+// var percentageOfMentors = Math.round(convertMentors);
+
+// console.log(`Student percentage: ${percentageOfStudents}%`);
+// console.log(`Student percentage: ${percentageOfMentors}%`);
+
+var numberOfStudents = 30;
+var numberOfMentors = 10;
+var total = numberOfStudents + numberOfMentors;
+
+var convertStudents = numberOfStudents / total * 100;
+var convertMentors = numberOfMentors / total * 100;
+
+console.log(`Student percentage: ${convertStudents}%`);
+console.log(`Mentor percentage: ${convertMentors}%`);
+
diff --git a/exercises/J-functions/exercise.js b/exercises/J-functions/exercise.js
index 0ae5850e5..37d0820c9 100644
--- a/exercises/J-functions/exercise.js
+++ b/exercises/J-functions/exercise.js
@@ -1,7 +1,25 @@
-function halve(number) {
-  // complete the function here
+// function halve(number) {
+//   return number/2;
+// }
+
+// var result = halve(12);
+// var result1 = halve(20);
+// var result2 = halve(30);
+// var result3 = halve(100);
+
+// console.log(result);
+// console.log(result1);
+// console.log(result2);
+// console.log(result3);
+
+function divide(number) {
+  return number / 2;
 }
 
-var result = halve(12);
+var answer1 = divide(5);
+var answer2 = divide(10);
+var answer3 = divide(15);
 
-console.log(result);
+console.log(answer1);
+console.log(answer2);
+console.log(answer3);
\ No newline at end of file
diff --git a/exercises/J-functions/exercise2.js b/exercises/J-functions/exercise2.js
index 82ef5e780..dd5b1b514 100644
--- a/exercises/J-functions/exercise2.js
+++ b/exercises/J-functions/exercise2.js
@@ -1,7 +1,16 @@
-function triple(number) {
-  // complete function here
+// function triple(number) {
+//   return number*3
+// }
+
+// var result = triple(12);
+
+// console.log(result);
+
+// My copy.
+function threeTimes(number) {
+  return (number * 3)*3;
 }
 
-var result = triple(12);
+var answer = threeTimes(3);
 
-console.log(result);
+console.log(`The answer is ${answer}`)
\ No newline at end of file
diff --git a/exercises/K-functions-parameters/README.md b/exercises/K-functions-parameters/README.md
index 02ab2a844..c961dd87c 100644
--- a/exercises/K-functions-parameters/README.md
+++ b/exercises/K-functions-parameters/README.md
@@ -42,7 +42,7 @@ function add(num1, num2) {
 
 * Write a function that takes a name (a string) and returns a greeting
 
-## Expected result
+## Expected result 
 
 ```
 Hello, my name is Daniel
diff --git a/exercises/K-functions-parameters/exercise.js b/exercises/K-functions-parameters/exercise.js
index 8d5db5e69..c4d6cd86d 100644
--- a/exercises/K-functions-parameters/exercise.js
+++ b/exercises/K-functions-parameters/exercise.js
@@ -1,9 +1,19 @@
 // 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; // Calculate the result of the function and return it
+// }
+
+// // Assign the result of calling the function the variable `result`
+// var result = multiply(3, 4);
+
+// console.log(result);
+
+// My copy.
+function multiply(num1, num2) {
+    return num1 * num2;
 }
 
-// Assign the result of calling the function the variable `result`
-var result = multiply(3, 4);
+let answer = multiply(5, 10);
+
+console.log(answer);
 
-console.log(result);
diff --git a/exercises/K-functions-parameters/exercise2.js b/exercises/K-functions-parameters/exercise2.js
index db7a8904b..e629bf1c4 100644
--- a/exercises/K-functions-parameters/exercise2.js
+++ b/exercises/K-functions-parameters/exercise2.js
@@ -1,5 +1,16 @@
-// Declare your function first
+// function divide(num1, num2){
+//     return num1/num2;
+// }// Declare your function first
 
-var result = divide(3, 4);
+// var result = divide(3, 4);
 
-console.log(result);
+// console.log(result);
+
+// My copy.
+function divide(num1, num2) {
+    return num1 / num2;
+}
+
+let answer = divide(5, 10);
+
+console.log(Math.round(answer));
\ No newline at end of file
diff --git a/exercises/K-functions-parameters/exercise3.js b/exercises/K-functions-parameters/exercise3.js
index 537e9f4ec..dbd54634d 100644
--- a/exercises/K-functions-parameters/exercise3.js
+++ b/exercises/K-functions-parameters/exercise3.js
@@ -1,5 +1,15 @@
-// Write your function here
+// function createGreeting(name){
+//     return `Hello, my name is ${name}`;
+// }// Write your function here
 
-var greeting = createGreeting("Daniel");
+// var greeting = createGreeting("Daniel");
 
-console.log(greeting);
+// console.log(greeting);
+
+function standardGreeting(firstName) {
+    return `Hello my firstname is ${firstName}`
+}
+
+let greeting = standardGreeting("Douglas");
+
+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..d848e3ab8 100644
--- a/exercises/K-functions-parameters/exercise4.js
+++ b/exercises/K-functions-parameters/exercise4.js
@@ -1,5 +1,17 @@
-// Declare your function first
+// function add(num1, num2) {
+//     return num1+num2;
+// }// Declare your function first
 
-// Call the function and assign to a variable `sum`
+// var sum = add(13,124);// Call the function and assign to a variable `sum`
 
-console.log(sum);
+// console.log(sum);
+
+// My Copy.
+
+function adding(num1, num2) {
+    return num1 + num2;
+}
+
+let sum = adding(5, 10);
+
+console.log(sum);
\ No newline at end of file
diff --git a/exercises/K-functions-parameters/exercise5.js b/exercises/K-functions-parameters/exercise5.js
index 7c5bcd605..ff2f20f82 100644
--- a/exercises/K-functions-parameters/exercise5.js
+++ b/exercises/K-functions-parameters/exercise5.js
@@ -1,5 +1,16 @@
-// Declare your function here
+// function createLongGreeting(name,age){
+//     return`Hello, my name is ${name} and I'm ${age} years old`
+// }// Declare your function here
 
-const greeting = createLongGreeting("Daniel", 30);
+// const greeting = createLongGreeting("Daniel", 30);
 
-console.log(greeting);
+// console.log(greeting);
+
+// My copy.
+function nameAgeGreeting(yourName, yourAge) {
+    return `My name is ${yourName} and I'm ${yourAge} years old.`;
+}
+
+let greeting = nameAgeGreeting("Douglas", 47);
+
+console.log(greeting);
\ No newline at end of file
diff --git a/exercises/L-functions-nested/exercise.js b/exercises/L-functions-nested/exercise.js
index a5d377442..c9026feb9 100644
--- a/exercises/L-functions-nested/exercise.js
+++ b/exercises/L-functions-nested/exercise.js
@@ -1,5 +1,102 @@
-var mentor1 = "Daniel";
-var mentor2 = "Irina";
-var mentor3 = "Mimi";
-var mentor4 = "Rob";
-var mentor5 = "Yohannes";
+// function percentage(num,total) {
+//     return (num/total*100);
+// }
+
+// var numberOfStudents = 15;
+// var numberOfMentors = 8;
+// var total = numberOfStudents + numberOfMentors;
+// var totalPercentage = percentage(numberOfStudents,numberOfMentors,total);
+
+// function initialMessage(numberOfStudents, numberOfMentors){
+//     message = `totalPercentage: ${numberOfStudents} ${numberOfMentors} ${Math.round(percentage)}%`;
+//     return message;
+// }
+
+// console.log(totalPercentage);
+
+// Function for calculating percentages.
+
+function percentage(num, total) {
+    return Math.round((num / total) * 100);
+}
+
+// Variables used for calculating the percentages.
+const numberOfStudents = 33;
+const numberOfMentors = 13;
+const total = numberOfStudents + numberOfMentors;
+let percentageStudents = percentage(numberOfStudents, total);
+let percentageMentors = percentage(numberOfMentors, total);
+
+// Function for creating the message.
+function percentageType(groupName, percentageOfGroupName) {
+    return groupName + percentageOfGroupName;
+}
+
+// Variables for creating the output message.
+let students = percentageType("Percentage Students: ", percentageStudents);
+let mentors = percentageType("Percentage Mentors: ", percentageMentors);
+
+// This one is using the variables above to output the message.
+console.log(students+"%");
+console.log(mentors+"%");
+// I need help with getting % added.
+
+This one is interpolation to create the message.
+    
+console.log(`Percentage Students: ${percentageStudents}%`);
+console.log(`Pencentage Mentors: ${percentageMentors}%`);
+
+
+
+
+
+
+
+
+
+
+
+// var mentor1 = "Daniel";
+// var mentor2 = "Irina";
+// var mentor3 = "Mimi";
+// var mentor4 = "Rob";
+// var mentor5 = "Yohannes";
+
+// function shoutyGreeting(name){
+//     var greeting = name.toUpperCase();
+//     return greeting = `HELLO ${greeting}`;
+// }
+
+// var greeting1 = shoutyGreeting(mentor1);
+// var greeting2 = shoutyGreeting(mentor2);
+// var greeting3 = shoutyGreeting(mentor3);
+// var greeting4 = shoutyGreeting(mentor4);
+// var greeting5 = shoutyGreeting(mentor5);
+
+let mentorA = "daniel";
+let mentorB = "irina";
+let mentorC = "mimi";
+let mentorD = "rob";
+let mentorE = "yohannes";
+
+function shoutyGreeting(mentorName) {
+    return "Hello " + mentorName + ".";
+}
+
+let greet1 = shoutyGreeting(mentorA.toUpperCase())
+let greet2 = shoutyGreeting(mentorB.toUpperCase())
+let greet3 = shoutyGreeting(mentorC.toUpperCase())
+let greet4 = shoutyGreeting(mentorD.toUpperCase())
+let greet5 = shoutyGreeting(mentorE.toUpperCase())
+
+console.log(greet1);
+console.log(greet2);
+console.log(greet3);
+console.log(greet4);
+console.log(greet5);
+
+// console.log(greeting1);
+// console.log(greeting2);
+// console.log(greeting3);
+// console.log(greeting4);
+// console.log(greeting5);
\ No newline at end of file
diff --git a/extra/1-currency-conversion.js b/extra/1-currency-conversion.js
index 70a2fe863..c9ecaf8b7 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(price) {
+  let converting = price * 1.4;
+  return converting;
+}
 
 /*
   CURRENCY FORMATTING
@@ -15,7 +18,10 @@ 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(price) {
+  let conversion = price * (5.7 * 0.99);
+  return conversion
+}
 
 /* ======= 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 067dd0f5b..08dec3dc2 100644
--- a/extra/2-piping.js
+++ b/extra/2-piping.js
@@ -16,26 +16,31 @@
   the final result to the variable goodCode
 */
 
-function add() {
-
+function add(number1, number2) {
+    return number1 + number2;
 }
 
-function multiply() {
-
+function multiply(number1, number2) {
+    return number1 * number2;
 }
 
-function format() {
-
+function format(numbers) {
+    let formatNumber = `"£"${number}`;
+    return formatNumber;
 }
 
-const startingValue = 2
+const startingValue = format(multiply((add(startingValue, 10), 2)));
 
 // Why can this code be seen as bad practice? Comment your answer.
-let badCode = 
+let badCode = startingValue; //When my code breaks, it will be difficult to see where I went wrong. Other coders will find my code difficult to read.
 
 /* BETTER PRACTICE */
 
-let goodCode = 
+let adding = add(startingValue, 10); //used add function.
+let multiplying = multiply(`${adding}`, 2); //used multiply function.
+let formatting = format(`${multiplying}`); //used formatting function.
+
+let goodCode = formatting; //Myself and Other coders can see clearly how I get to my result.
 
 /* ======= 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 0a21afd1b..6bc206d08 100644
--- a/mandatory/1-syntax-errors.js
+++ b/mandatory/1-syntax-errors.js
@@ -1,18 +1,21 @@
 // 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;
+    let total = a + b;
 
-    return "The total is total"
+    return "The total is " + total;
 }
 
+console.log(getTotal);
+
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====
diff --git a/mandatory/2-logic-error.js b/mandatory/2-logic-error.js
index 3c578ad87..f2076f517 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;
 }
 
 /* 
diff --git a/mandatory/3-function-output.js b/mandatory/3-function-output.js
index c9221a200..2dbcc49d2 100644
--- a/mandatory/3-function-output.js
+++ b/mandatory/3-function-output.js
@@ -1,18 +1,32 @@
 // Add comments to explain what this function does. You're meant to use Google!
+
+// Math.random() returns a random number between 0 (inclusive),  and 1 (exclusive):
+// For example: 0.40020936983011146
+// Math.random() always returns a number lower than 1.
 function getNumber() {
   return Math.random() * 10;
-}
+} // The Math.random() function returns a floating-point, pseudo-random number in the range 0 to less than 1 (inclusive of 0, but not 1)with approximately uniform distribution over that range — which you can then scale to your desired range. so the getnumber function multiplies the psuedo random number between 0 and 10 however not 10.
 
 // Add comments to explain what this function does. You're meant to use Google!
+// The concat() method is used to join two or more arrays.
+// This method does not change the existing arrays, but returns a new array, containing the values of the joined arrays.
 function s(w1, w2) {
   return w1.concat(w2);
 }
+//I think this function allows 2 strings to be added together and create or in this case return a new string
 
 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}`;
 }
 
+//Here, I called the last function.
+let threeWords = concatenate("I", "don't know", "what to do here!");
+
+// Here, I'm checking my output.
+console.log(threeWords);
+
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index c9e41c691..852da204c 100644
--- a/mandatory/4-tax.js
+++ b/mandatory/4-tax.js
@@ -5,7 +5,9 @@
   Sales tax is 20% of the price of the product
 */
 
-function calculateSalesTax() {}
+function calculateSalesTax(price) {
+  return price + (price*0.2);
+}
 
 /*
   CURRENCY FORMATTING
@@ -17,8 +19,11 @@ function calculateSalesTax() {}
   Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
 */
 
-function addTaxAndFormatCurrency() {}
-
+function addTaxAndFormatCurrency(numberToBeTaxed) {
+  const taxedValue = calculateSalesTax(numberToBeTaxed); //return taxed value.
+  const formatValue = `£${taxedValue.toFixed(2)}`; //formatted tax value.
+  return formatValue;
+}
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====