diff --git a/exercises/B-hello-world/exercise.js b/exercises/B-hello-world/exercise.js
index b179ee953..dd8483bbd 100644
--- a/exercises/B-hello-world/exercise.js
+++ b/exercises/B-hello-world/exercise.js
@@ -1 +1 @@
-console.log("Hello world");
+console.log("Salam Duniya");
diff --git a/exercises/C-variables/exercise.js b/exercises/C-variables/exercise.js
index a6bbb9786..7beea3261 100644
--- a/exercises/C-variables/exercise.js
+++ b/exercises/C-variables/exercise.js
@@ -1,3 +1,5 @@
 // Start by creating a variable `greeting`
-
+var 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..e87d13c93 100644
--- a/exercises/D-strings/exercise.js
+++ b/exercises/D-strings/exercise.js
@@ -1,3 +1,5 @@
 // Start by creating a variable `message`
-
+var message="This is a string";
+var 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..14ef3bca3 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 = "Daniel";
+
+var greeting = greetingStart + name;
+
+console.log(greeting); // Logs "Hello, my name is Daniel"
 
-console.log(message);
diff --git a/exercises/F-strings-methods/exercise.js b/exercises/F-strings-methods/exercise.js
index 2cffa6a81..3ca5f3bea 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`
+var name = "Daniel";
+var nameLength = name.length;
+var combinedstring ="My name is "+ name +" and my name is "+ nameLength +" characters long";
+console.log(combinedstring); // Logs 6
 
-console.log(message);
diff --git a/exercises/F-strings-methods/exercise2.js b/exercises/F-strings-methods/exercise2.js
index b4b46943d..3e06970b6 100644
--- a/exercises/F-strings-methods/exercise2.js
+++ b/exercises/F-strings-methods/exercise2.js
@@ -1,3 +1,5 @@
 const name = " Daniel  ";
+var nameLength = name.length;
+var combinedstring ="My name is "+ name.trim +" and my name is "+ nameLength +" characters long";
+console.log(combinedstring);
 
-console.log(message);
diff --git a/exercises/G-numbers/exercise.js b/exercises/G-numbers/exercise.js
index 49e7bc00b..675a9674b 100644
--- a/exercises/G-numbers/exercise.js
+++ b/exercises/G-numbers/exercise.js
@@ -1 +1,7 @@
 // Start by creating a variables `numberOfStudents` and `numberOfMentors`
+var numberOfStudents =15;
+var numberOfMentors = 8;
+console.log("Number of students:"+numberOfStudents);
+console.log("Number of mentors:"+numberOfMentors);
+var total=numberOfStudents+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..801666fab 100644
--- a/exercises/I-floats/exercise.js
+++ b/exercises/I-floats/exercise.js
@@ -1,2 +1,7 @@
 var numberOfStudents = 15;
 var numberOfMentors = 8;
+var total=numberOfStudents+numberOfMentors;
+var percentage=(numberOfStudents/total)*100;
+console.log("Percentage students: "+ Math.round(percentage)+"%");
+percentage=(numberOfMentors/total)*100;
+console.log("Percentage Mentors: "+Math.round(percentage)+"%");
\ No newline at end of file
diff --git a/exercises/J-functions/README.md b/exercises/J-functions/README.md
index 22105ca2a..3fb4838e7 100644
--- a/exercises/J-functions/README.md
+++ b/exercises/J-functions/README.md
@@ -38,5 +38,5 @@ console.log(result); // 4
 ## Expected result
 
 ```
-36
+1728
 ```
diff --git a/exercises/J-functions/exercise.js b/exercises/J-functions/exercise.js
index 0ae5850e5..c40329483 100644
--- a/exercises/J-functions/exercise.js
+++ b/exercises/J-functions/exercise.js
@@ -1,5 +1,5 @@
 function halve(number) {
-  // complete the function here
+  return number/2 ;
 }
 
 var result = halve(12);
diff --git a/exercises/J-functions/exercise2.js b/exercises/J-functions/exercise2.js
index 82ef5e780..4179c8d9e 100644
--- a/exercises/J-functions/exercise2.js
+++ b/exercises/J-functions/exercise2.js
@@ -1,5 +1,6 @@
 function triple(number) {
   // complete function here
+  return number*number*number;
 }
 
 var result = triple(12);
diff --git a/exercises/K-functions-parameters/exercise.js b/exercises/K-functions-parameters/exercise.js
index 8d5db5e69..5be5c19c2 100644
--- a/exercises/K-functions-parameters/exercise.js
+++ b/exercises/K-functions-parameters/exercise.js
@@ -1,6 +1,7 @@
 // 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`
diff --git a/exercises/K-functions-parameters/exercise2.js b/exercises/K-functions-parameters/exercise2.js
index db7a8904b..aeb6ebedb 100644
--- a/exercises/K-functions-parameters/exercise2.js
+++ b/exercises/K-functions-parameters/exercise2.js
@@ -1,5 +1,7 @@
 // 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..57fe23a0a 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(name) {
+    return "Hello , my name is "+name;
+}
 var greeting = createGreeting("Daniel");
 
 console.log(greeting);
diff --git a/exercises/K-functions-parameters/exercise4.js b/exercises/K-functions-parameters/exercise4.js
index 7ab44589e..6a56be320 100644
--- a/exercises/K-functions-parameters/exercise4.js
+++ b/exercises/K-functions-parameters/exercise4.js
@@ -1,5 +1,7 @@
 // Declare your function first
-
+function add(num1,num2){
+    return num1+num2;
+}
 // Call the function and assign to a variable `sum`
-
+var 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..66b605c20 100644
--- a/exercises/K-functions-parameters/exercise5.js
+++ b/exercises/K-functions-parameters/exercise5.js
@@ -1,5 +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);
 
 console.log(greeting);
diff --git a/exercises/L-functions-nested/exercise.js b/exercises/L-functions-nested/exercise.js
index a5d377442..8260c3f87 100644
--- a/exercises/L-functions-nested/exercise.js
+++ b/exercises/L-functions-nested/exercise.js
@@ -3,3 +3,16 @@ var mentor2 = "Irina";
 var mentor3 = "Mimi";
 var mentor4 = "Rob";
 var mentor5 = "Yohannes";
+
+function changetouppercase(name){
+    shoutyGreeting(name.toUpperCase())
+}
+
+function shoutyGreeting(name){
+    console.log("HELLO "+ name);
+}
+changetouppercase(mentor1);
+changetouppercase(mentor2);
+changetouppercase(mentor3);
+changetouppercase(mentor4);
+changetouppercase(mentor5);
\ No newline at end of file
diff --git a/extra/1-currency-conversion.js b/extra/1-currency-conversion.js
index 75b3c6aab..3e000060b 100644
--- a/extra/1-currency-conversion.js
+++ b/extra/1-currency-conversion.js
@@ -5,7 +5,9 @@
   Write a function that converts a price to USD (exchange rate is 1.4 $ to £)
 */
 
-function convertToUSD() {}
+function convertToUSD(price) {
+return price*1.4;
+}
 
 /*
   CURRENCY CONVERSION
@@ -15,7 +17,10 @@ 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(priceinpounds) {
+  return Number((priceinpounds*0.99*5.7).toFixed(2));
+
+}
 
 /* ======= 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..a3675d287 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(name1, age){
+  return "Hello, my name is "+ name1 +" and I am "+ age +" years old";
+}
 
 function getTotal(a, b) {
-  total = a ++ b;
-
-  return "The total is total";
+  total = a + b;
+  return "The total is "+total;
 }
 
 /* 
diff --git a/mandatory/2-logic-error.js b/mandatory/2-logic-error.js
index 9cca7603b..4902e77f2 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..68419b1b0 100644
--- a/mandatory/3-function-output.js
+++ b/mandatory/3-function-output.js
@@ -1,16 +1,18 @@
 // Add comments to explain what this function does. You're meant to use Google!
 function getRandomNumber() {
-  return Math.random() * 10;
+  return Math.random() * 10;//Math.random()*10 returns a random number between 0 and 10
 }
 
 // Add comments to explain what this function does. You're meant to use Google!
 function combine2Words(word1, word2) {
-  return word1.concat(word2);
+  return word1.concat(word2);//The concat() method appends a string to the end of another 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.concat(" ",secondWord).concat(" ",thirdWord);
+  
 }
 
 /* 
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index ba77c7ae2..a7c9bff33 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*1.2;
+}
 
 /*
   CURRENCY FORMATTING
@@ -17,7 +19,9 @@ function calculateSalesTax() {}
   Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
 */
 
-function addTaxAndFormatCurrency() {}
+function addTaxAndFormatCurrency(price) {
+return "£"+ calculateSalesTax(price).toFixed(2) ;
+}
 
 /* 
 ===================================================
diff --git a/package.json b/package.json
index 93e0861e3..9e7f2ffeb 100644
--- a/package.json
+++ b/package.json
@@ -14,15 +14,21 @@
     "url": "https://github.com/CodeYourFuture/JavaScript-Core-1-Coursework-Week1/issues"
   },
   "jest": {
-    "setupFilesAfterEnv": ["jest-extended"],
+    "setupFilesAfterEnv": [
+      "jest-extended"
+    ],
     "projects": [
       {
         "displayName": "mandatory",
-        "testMatch": ["<rootDir>/mandatory/*.js"]
+        "testMatch": [
+          "<rootDir>/mandatory/*.js"
+        ]
       },
       {
         "displayName": "extra",
-        "testMatch": ["<rootDir>/extra/*.js"]
+        "testMatch": [
+          "<rootDir>/extra/*.js"
+        ]
       }
     ]
   },