diff --git a/exercises/B-hello-world/exercise.js b/exercises/B-hello-world/exercise.js
index b179ee953..5f29038f1 100644
--- a/exercises/B-hello-world/exercise.js
+++ b/exercises/B-hello-world/exercise.js
@@ -1 +1,6 @@
-console.log("Hello world");
+console.log("Hello World. I just started learning JavaScript!");
+
+console.log("I am too strong and I can do it!")
+console.log(`It is my first coding exercise`)
+console.log('Hello World. I just started learning JavaScript!')
+console.log(45)
diff --git a/exercises/C-variables/exercise.js b/exercises/C-variables/exercise.js
index a6bbb9786..1101e702c 100644
--- a/exercises/C-variables/exercise.js
+++ b/exercises/C-variables/exercise.js
@@ -1,3 +1,9 @@
 // Start by creating a variable `greeting`
 
+const 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..e4552f5d3 100644
--- a/exercises/D-strings/exercise.js
+++ b/exercises/D-strings/exercise.js
@@ -1,3 +1,11 @@
 // Start by creating a variable `message`
 
-console.log(message);
+// var message = "I am a trainer in CYF";
+// var messageType = typeof message;
+// console.log(messageType); 
+
+
+let message="This is a string"
+let  messageType = typeof message;
+console.log(message)
+console.log(messageType);
\ No newline at end of file
diff --git a/exercises/E-strings-concatenation/exercise.js b/exercises/E-strings-concatenation/exercise.js
index 2cffa6a81..1d4270332 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 myName = "Mo nahvi";
+var greeting = "Hello, my name is";
+let message =  greeting + " " + myName;
 console.log(message);
diff --git a/exercises/F-strings-methods/exercise.js b/exercises/F-strings-methods/exercise.js
index 2cffa6a81..cec0ef6da 100644
--- a/exercises/F-strings-methods/exercise.js
+++ b/exercises/F-strings-methods/exercise.js
@@ -1,3 +1,7 @@
 // Start by creating a variable `message`
+var name = "Mohammad"
+var message = name.length;
+var nameLowerCase = name.toLowerCase();
 
 console.log(message);
+console.log(nameLowerCase)
diff --git a/exercises/F-strings-methods/exercise2.js b/exercises/F-strings-methods/exercise2.js
index b4b46943d..e799ab56e 100644
--- a/exercises/F-strings-methods/exercise2.js
+++ b/exercises/F-strings-methods/exercise2.js
@@ -1,3 +1,7 @@
-const name = " Daniel  ";
-
+let myName = "Mohammad ";
+var greeting = "My name is ";
+let sent = "and my name is 8 characters long"
+let message =  greeting + myName + sent;
 console.log(message);
+
+
diff --git a/exercises/K-functions-parameters/exercise.js b/exercises/K-functions-parameters/exercise.js
index 8d5db5e69..5ecad1c75 100644
--- a/exercises/K-functions-parameters/exercise.js
+++ b/exercises/K-functions-parameters/exercise.js
@@ -1,5 +1,8 @@
 // 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
 }
 
diff --git a/exercises/K-functions-parameters/exercise2.js b/exercises/K-functions-parameters/exercise2.js
index db7a8904b..9827d7673 100644
--- a/exercises/K-functions-parameters/exercise2.js
+++ b/exercises/K-functions-parameters/exercise2.js
@@ -1,5 +1,11 @@
 // Declare your function first
 
+// var result = divide(3, 4);
+
+// console.log(result);
+function divide(num1,num2) {
+return num1 / num2;
+}
 var result = divide(3, 4);
 
 console.log(result);
diff --git a/exercises/K-functions-parameters/exercise4.js b/exercises/K-functions-parameters/exercise4.js
index 7ab44589e..1c71a189b 100644
--- a/exercises/K-functions-parameters/exercise4.js
+++ b/exercises/K-functions-parameters/exercise4.js
@@ -2,4 +2,8 @@
 
 // Call the function and assign to a variable `sum`
 
-console.log(sum);
+// console.log(sum);
+function sum(num1, num2) {
+    return num1 + num2
+}
+console.log(sum(13, 124));
\ No newline at end of file
diff --git a/exercises/K-functions-parameters/exercise5.js b/exercises/K-functions-parameters/exercise5.js
index 7c5bcd605..3b5c3dc23 100644
--- a/exercises/K-functions-parameters/exercise5.js
+++ b/exercises/K-functions-parameters/exercise5.js
@@ -1,5 +1,6 @@
 // Declare your function here
 
-const greeting = createLongGreeting("Daniel", 30);
-
-console.log(greeting);
+function createLongGreeting(name,age){
+    return "Hello ,my name is "+name+"and i'm "+age+ " years old"
+}
+ const greeting = createLongGreeting("Daniel", 30);
diff --git a/exercises/L-functions-nested/exercise.js b/exercises/L-functions-nested/exercise.js
index a5d377442..9ae7a166d 100644
--- a/exercises/L-functions-nested/exercise.js
+++ b/exercises/L-functions-nested/exercise.js
@@ -1,5 +1,23 @@
-var mentor1 = "Daniel";
-var mentor2 = "Irina";
-var mentor3 = "Mimi";
-var mentor4 = "Rob";
-var mentor5 = "Yohannes";
+// 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";
+
+function nameToUpperCase(name){
+    return name.toUpperCase();
+}
+function greeting(name){
+    return `Hello ${nameToUpperCase(name)}`;
+}
+function result(name){
+    return console.log(greeting(name));
+}
+result(mentor1);
+result(mentor3)
\ No newline at end of file
diff --git a/mandatory/1-syntax-errors.js b/mandatory/1-syntax-errors.js
index a10cc9ac2..adf6ac4e1 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";
+  return "Hello, my name is " + name + "and I am " + age + "years old";
 
-function getTotal(a, b) {
-  total = a ++ b;
+function getTotal(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..881472346 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..1a558af4d 100644
--- a/mandatory/3-function-output.js
+++ b/mandatory/3-function-output.js
@@ -1,16 +1,17 @@
 // Add comments to explain what this function does. You're meant to use Google!
+ // It get a number between 0 to 10
 function getRandomNumber() {
   return Math.random() * 10;
 }
 
 // Add comments to explain what this function does. You're meant to use Google!
+//It connect the word together 
 function combine2Words(word1, word2) {
   return word1.concat(word2);
 }
 
 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..0936362f6 100644
--- a/mandatory/4-tax.js
+++ b/mandatory/4-tax.js
@@ -5,7 +5,12 @@
   Sales tax is 20% of the price of the product.
 */
 
-function calculateSalesTax() {}
+function calculateSalesTax(newPrice) {
+  return newPrice * 0.2 + newPrice
+  
+}
+
+console.log(calculateSalesTax(15)) 
 
 /*
   CURRENCY FORMATTING
@@ -17,7 +22,13 @@ function calculateSalesTax() {}
   Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
 */
 
-function addTaxAndFormatCurrency() {}
+function addTaxAndFormatCurrency(addPrice) {
+  let  newP= calculateSalesTax(addPrice);
+  let deci = newP.toFixed(2);
+  return `£ ${deci}`
+}
+
+console.log(addTaxAndFormatCurrency(50))
 
 /* 
 ===================================================
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"
+        ]
       }
     ]
   },