diff --git a/exercises/B-hello-world/exercise.js b/exercises/B-hello-world/exercise.js
index b179ee953..f15f0e96a 100644
--- a/exercises/B-hello-world/exercise.js
+++ b/exercises/B-hello-world/exercise.js
@@ -1 +1,6 @@
 console.log("Hello world");
+console.log("My neme is Ahmed");
+console.log("I'm Eritrian");
+console.log("I'm from Manchester");
+
+
diff --git a/exercises/C-variables/exercise.js b/exercises/C-variables/exercise.js
index a6bbb9786..461ed5c0d 100644
--- a/exercises/C-variables/exercise.js
+++ b/exercises/C-variables/exercise.js
@@ -1,3 +1,5 @@
 // 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..d50b547c1 100644
--- a/exercises/D-strings/exercise.js
+++ b/exercises/D-strings/exercise.js
@@ -1,3 +1,7 @@
 // Start by creating a variable `message`
 
-console.log(message);
+var message = "Hello World";
+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..f99cafed3 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`
+var greetingStart = "Hi guys my name is ";
+let fname = "Danti";
+var message = greetingStart + fname;
 
 console.log(message);
diff --git a/exercises/F-strings-methods/exercise.js b/exercises/F-strings-methods/exercise.js
index 2cffa6a81..2e49c97a9 100644
--- a/exercises/F-strings-methods/exercise.js
+++ b/exercises/F-strings-methods/exercise.js
@@ -1,3 +1,4 @@
 // Start by creating a variable `message`
-
-console.log(message);
+let myname = "Danti";
+let message = "My name is" + myname + "and my name is " + myname.length +" characters long";
+console.log(message);
\ No newline at end of file
diff --git a/exercises/F-strings-methods/exercise2.js b/exercises/F-strings-methods/exercise2.js
index b4b46943d..daa0e8c9a 100644
--- a/exercises/F-strings-methods/exercise2.js
+++ b/exercises/F-strings-methods/exercise2.js
@@ -1,3 +1,4 @@
-const name = " Daniel  ";
-
+const myName = " Daniel  ";
+let newName = myName.trim();
+const message = "My name is" + myName + "and my name is " + newName.length + " characters long";
 console.log(message);
diff --git a/exercises/G-numbers/exercise.js b/exercises/G-numbers/exercise.js
index 49e7bc00b..6ec5d3977 100644
--- a/exercises/G-numbers/exercise.js
+++ b/exercises/G-numbers/exercise.js
@@ -1 +1,6 @@
 // Start by creating a variables `numberOfStudents` and `numberOfMentors`
+let numberOfStudents = 2;
+let numberOfMentors = 6;
+console.log("Number of mentors: " + numberOfMentors);
+console.log("Number of students: " + numberOfStudents);
+console.log("Total number of students and mentors: " + (numberOfMentors + numberOfStudents));
\ No newline at end of file
diff --git a/exercises/I-floats/exercise.js b/exercises/I-floats/exercise.js
index a5bbcd852..368dbc29f 100644
--- a/exercises/I-floats/exercise.js
+++ b/exercises/I-floats/exercise.js
@@ -1,2 +1,6 @@
-var numberOfStudents = 15;
-var numberOfMentors = 8;
+// var numberOfStudents = 15;
+// var numberOfMentors = 8;
+var preciseAge = 30.612437;
+var result = preciseAge / 10;
+var resultWhole = Math.round(result);
+console.log(resultWhole + ": " + "%");
\ No newline at end of file
diff --git a/exercises/J-functions/exercise.js b/exercises/J-functions/exercise.js
index 0ae5850e5..0fc4c3655 100644
--- a/exercises/J-functions/exercise.js
+++ b/exercises/J-functions/exercise.js
@@ -1,5 +1,6 @@
 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..468d45596 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 * 3;
 }
 
 var result = triple(12);
diff --git a/exercises/K-functions-parameters/exercise.js b/exercises/K-functions-parameters/exercise.js
index 8d5db5e69..ffd252544 100644
--- a/exercises/K-functions-parameters/exercise.js
+++ b/exercises/K-functions-parameters/exercise.js
@@ -1,9 +1,10 @@
 // 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`
 var result = multiply(3, 4);
-
+multiply()
 console.log(result);
diff --git a/exercises/K-functions-parameters/exercise2.js b/exercises/K-functions-parameters/exercise2.js
index db7a8904b..42cc2aa7d 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(a , b) {
+    return a / b;
+}
+
 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..b3fde68d8 100644
--- a/exercises/K-functions-parameters/exercise3.js
+++ b/exercises/K-functions-parameters/exercise3.js
@@ -1,5 +1,8 @@
 // Write your function here
+function createGreeting(myName) {
+    return "Hello, my name is " + myName;
+}
 
-var greeting = createGreeting("Daniel");
+var greeting = createGreeting("Danti");
 
 console.log(greeting);
diff --git a/exercises/K-functions-parameters/exercise4.js b/exercises/K-functions-parameters/exercise4.js
index 7ab44589e..ab6dcf4b1 100644
--- a/exercises/K-functions-parameters/exercise4.js
+++ b/exercises/K-functions-parameters/exercise4.js
@@ -1,5 +1,7 @@
 // Declare your function first
-
+function sum (a,b) {
+    return  sum = a + b;
+}
 // Call the function and assign to a variable `sum`
-
+sum(13,124)
 console.log(sum);
diff --git a/exercises/K-functions-parameters/exercise5.js b/exercises/K-functions-parameters/exercise5.js
index 7c5bcd605..0c0a4c65b 100644
--- a/exercises/K-functions-parameters/exercise5.js
+++ b/exercises/K-functions-parameters/exercise5.js
@@ -1,5 +1,21 @@
 // Declare your function here
+function createLongGreeting(a,b) {
+    return "Hello My name is " + a + "and I'm " + b + "years old";
+}
 
-const greeting = createLongGreeting("Daniel", 30);
+
+
+const greeting = createLongGreeting("Danti ", 30);
 
 console.log(greeting);
+
+
+
+
+// - Write a function that takes a name (a string) and an age (a number) and returns a greeting (a string)
+
+// ## Expected result
+
+// ```
+// 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..b074f0bf4 100644
--- a/exercises/L-functions-nested/exercise.js
+++ b/exercises/L-functions-nested/exercise.js
@@ -3,3 +3,14 @@ var mentor2 = "Irina";
 var mentor3 = "Mimi";
 var mentor4 = "Rob";
 var mentor5 = "Yohannes";
+
+
+function danti(a) {
+    return "HELOW";
+
+}
+console.log(danti() + " " + mentor1.toUpperCase() );
+console.log(danti() + " " + mentor2.toUpperCase() );
+console.log(danti() + " " + mentor3.toUpperCase() );
+console.log(danti() + " " + mentor4.toUpperCase() );
+console.log(danti() + " " + mentor5.toUpperCase() );
\ No newline at end of file
diff --git a/mandatory/1-syntax-errors.js b/mandatory/1-syntax-errors.js
index a10cc9ac2..255ab837c 100644
--- a/mandatory/1-syntax-errors.js
+++ b/mandatory/1-syntax-errors.js
@@ -1,18 +1,27 @@
 // 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";
+addNumbers(3,4,6);
+console.log(addNumbers(3,4,6))
+
+function introduceMe(name, age){
+  return "Hello, my name is " + name + " and I am " + age + " years old";
+}
+
+introduceMe("Sonjide", 27);
+console.log(introduceMe("Sonjide", 27))
 
 function getTotal(a, b) {
-  total = a ++ b;
+  let total = a + b;
 
-  return "The total is total";
+  return "The total is " + total;
 }
 
+getTotal(23,5);
+console.log(getTotal(23,5));
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====
diff --git a/mandatory/2-logic-error.js b/mandatory/2-logic-error.js
index 9cca7603b..78e99bbda 100644
--- a/mandatory/2-logic-error.js
+++ b/mandatory/2-logic-error.js
@@ -1,18 +1,19 @@
 // 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;
+ 
 }
-
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====
diff --git a/mandatory/3-function-output.js b/mandatory/3-function-output.js
index 5a953ba60..d8649b92b 100644
--- a/mandatory/3-function-output.js
+++ b/mandatory/3-function-output.js
@@ -1,14 +1,17 @@
 // Add comments to explain what this function does. You're meant to use Google!
-function getRandomNumber() {
-  return Math.random() * 10;
+function getRandomNumber() { 
+  return Math.random() * 10; // This function multiply tow number and the first number change it to whole number to get the result whole number.
 }
 
 // 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);  // This function work to marge to word together.
 }
 
 function concatenate(firstWord, secondWord, thirdWord) {
+  return firstWord.concat(" ", 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.
 }
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index ba77c7ae2..39f579685 100644
--- a/mandatory/4-tax.js
+++ b/mandatory/4-tax.js
@@ -5,7 +5,13 @@
   Sales tax is 20% of the price of the product.
 */
 
-function calculateSalesTax() {}
+function calculateSalesTax(product) {
+  let product1 = (product * 20) / 100 + product;
+return product1;
+
+}
+
+
 
 /*
   CURRENCY FORMATTING
@@ -17,7 +23,10 @@ function calculateSalesTax() {}
   Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
 */
 
-function addTaxAndFormatCurrency() {}
+function addTaxAndFormatCurrency(a) {
+  return "£" + calculateSalesTax(a).toFixed(2);
+}
+// console.log( addTaxAndFormatCurrency(calculateSalesTax(34)));
 
 /* 
 ===================================================