diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 000000000..6f3a2913e
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,3 @@
+{
+    "liveServer.settings.port": 5501
+}
\ No newline at end of file
diff --git a/exercises/B-hello-world/exercise.js b/exercises/B-hello-world/exercise.js
index b179ee953..ba09f99f6 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 JavaScript!");
+console.log("Hello word! my name is Yousef");
+console.log(27);
diff --git a/exercises/C-variables/exercise.js b/exercises/C-variables/exercise.js
index a6bbb9786..ec5237c12 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);
\ No newline at end of file
diff --git a/exercises/D-strings/exercise.js b/exercises/D-strings/exercise.js
index 2cffa6a81..aa3318fe6 100644
--- a/exercises/D-strings/exercise.js
+++ b/exercises/D-strings/exercise.js
@@ -1,3 +1,6 @@
 // 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..30c99adbc 100644
--- a/exercises/E-strings-concatenation/exercise.js
+++ b/exercises/E-strings-concatenation/exercise.js
@@ -1,3 +1,5 @@
 // Start by creating a variable `message`
-
+var greetingStart = "Hello, my name is ";
+var myName = "Yousef";
+var greeting = greetingStart + myName;
 console.log(message);
diff --git a/exercises/F-strings-methods/exercise.js b/exercises/F-strings-methods/exercise.js
index 2cffa6a81..e176daea7 100644
--- a/exercises/F-strings-methods/exercise.js
+++ b/exercises/F-strings-methods/exercise.js
@@ -1,3 +1,5 @@
 // Start by creating a variable `message`
-
+var fName = " Yousef  ";
+var nameLength = fName.length
+var message = "My name is " + fName + "and my name is " + nameLength + "characters long";
 console.log(message);
diff --git a/exercises/F-strings-methods/exercise2.js b/exercises/F-strings-methods/exercise2.js
index b4b46943d..74a72a17f 100644
--- a/exercises/F-strings-methods/exercise2.js
+++ b/exercises/F-strings-methods/exercise2.js
@@ -1,3 +1,5 @@
-const name = " Daniel  ";
-
+const fName =" Daniel"
+const readName = fName.trim();
+const nameLength = fName.length
+const message = "My name is " + readName + " and the length of my name" + nameLength; 
 console.log(message);
diff --git a/exercises/G-numbers/exercise.js b/exercises/G-numbers/exercise.js
index 49e7bc00b..7cc9564f0 100644
--- a/exercises/G-numbers/exercise.js
+++ b/exercises/G-numbers/exercise.js
@@ -1 +1,5 @@
 // Start by creating a variables `numberOfStudents` and `numberOfMentors`
+var numberOfStudents = 15
+var numberOfMentors = 8
+const sum = numberOfStudents + numberOfMentors;
+console.log(sum);
diff --git a/exercises/I-floats/exercise.js b/exercises/I-floats/exercise.js
index a5bbcd852..f13b180c3 100644
--- a/exercises/I-floats/exercise.js
+++ b/exercises/I-floats/exercise.js
@@ -1,2 +1,7 @@
 var numberOfStudents = 15;
 var numberOfMentors = 8;
+const total = numberOfStudents + numberOfMentors;
+const studentPercentage= (numberOfStudents / total) * 100;
+const mentorPercentage = (numberOfMentors / total) * 100;
+console.log(studentPercentage);
+console.log(mentorPercentage);
diff --git a/exercises/J-functions/exercise.js b/exercises/J-functions/exercise.js
index 0ae5850e5..4658b01c1 100644
--- a/exercises/J-functions/exercise.js
+++ b/exercises/J-functions/exercise.js
@@ -1,7 +1,6 @@
 function halve(number) {
   // complete the function here
+  return number / 2;
 }
-
-var result = halve(12);
-
+ const result = halve(12);
 console.log(result);
diff --git a/exercises/J-functions/exercise2.js b/exercises/J-functions/exercise2.js
index 82ef5e780..f62635fed 100644
--- a/exercises/J-functions/exercise2.js
+++ b/exercises/J-functions/exercise2.js
@@ -1,7 +1,8 @@
 function triple(number) {
   // complete function here
+  return number * 3 ;
 }
 
-var result = triple(12);
+const result = triple(12);
 
 console.log(result);
diff --git a/exercises/K-functions-parameters/exercise.js b/exercises/K-functions-parameters/exercise.js
index 8d5db5e69..e7be43f1e 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(a , b) {
   // Calculate the result of the function and return it
+  return a * b;
 }
 
 // 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..0cc9abe57 100644
--- a/exercises/K-functions-parameters/exercise2.js
+++ b/exercises/K-functions-parameters/exercise2.js
@@ -1,5 +1,7 @@
 // Declare your function first
-
-var result = divide(3, 4);
+function divide(a,b){
+    return a / b;
+}
+const 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..823e291ef 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..a77808db0 100644
--- a/exercises/K-functions-parameters/exercise4.js
+++ b/exercises/K-functions-parameters/exercise4.js
@@ -1,5 +1,8 @@
 // Declare your function first
+function add(a,b){
+    return a+b;
+}
 
 // Call the function and assign to a variable `sum`
-
+const 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..5be2d66c0 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 `My name is ${name} and I am ${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..5b63b6ff5 100644
--- a/exercises/L-functions-nested/exercise.js
+++ b/exercises/L-functions-nested/exercise.js
@@ -1,5 +1,16 @@
-var mentor1 = "Daniel";
-var mentor2 = "Irina";
-var mentor3 = "Mimi";
-var mentor4 = "Rob";
-var mentor5 = "Yohannes";
+const mentor1 = "Daniel";
+const mentor2 = "Irina";
+const mentor3 = "Mimi";
+const mentor4 = "Rob";
+const mentor5 = "Yohannes";
+const name = (mentor1, mentor2, mentor3, mentor4, mentor5);
+function greetingName(name){
+    const upperName = name.toUpperCase();
+    const message = " Hello " + upperName;
+    return message;
+}
+console.log(greetingName(mentor1));
+console.log(greetingName(mentor2));
+console.log(greetingName(mentor3));
+console.log(greetingName(mentor4));
+console.log(greetingName(mentor5));
\ No newline at end of file
diff --git a/mandatory/1-syntax-errors.js b/mandatory/1-syntax-errors.js
index a10cc9ac2..20050fb4f 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;
+  const total = a + b;
 
-  return "The total is total";
+  return "The total is " + total;
 }
 
+
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====
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..f248fccf8 100644
--- a/mandatory/3-function-output.js
+++ b/mandatory/3-function-output.js
@@ -2,15 +2,18 @@
 function getRandomNumber() {
   return Math.random() * 10;
 }
+// this function  means return a random number between 0(inclusive), and 10(exclusive)
 
 // Add comments to explain what this function does. You're meant to use Google!
 function combine2Words(word1, word2) {
   return word1.concat(word2);
 }
+// the diffrent selection of the set of element taken one by one,or some join toghether
 
 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);
 }
 
 /* 
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index ba77c7ae2..dc65462ea 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(price) {
+  return (price * 20) / 100;
+
+}
+
 
 /*
   CURRENCY FORMATTING