diff --git a/exercises/B-hello-world/exercise.js b/exercises/B-hello-world/exercise.js
index b179ee953..3419049a6 100644
--- a/exercises/B-hello-world/exercise.js
+++ b/exercises/B-hello-world/exercise.js
@@ -1 +1,9 @@
-console.log("Hello world");
+
+console.log("hello world");
+console.log("I just started learning JavaScript!");
+console.log("hi");
+
+
+
+
+
diff --git a/exercises/C-variables/exercise.js b/exercises/C-variables/exercise.js
index a6bbb9786..91e425647 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 = "Hey! I am a variable";
+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..d8d1e3cea 100644
--- a/exercises/D-strings/exercise.js
+++ b/exercises/D-strings/exercise.js
@@ -1,3 +1,5 @@
 // Start by creating a variable `message`
 
-console.log(message);
+let message = "this is text inside ' ' and the name is string"
+console.log(typeof message);
+
diff --git a/exercises/E-strings-concatenation/exercise.js b/exercises/E-strings-concatenation/exercise.js
index 2cffa6a81..ac16782be 100644
--- a/exercises/E-strings-concatenation/exercise.js
+++ b/exercises/E-strings-concatenation/exercise.js
@@ -1,3 +1,12 @@
 // Start by creating a variable `message`
 
+let students = "we are seven students";
+
+let teacher = " and 2 teachers";
+
+let message = students + teacher + " working in the proyect.";
+
+
+
+
 console.log(message);
diff --git a/exercises/F-strings-methods/exercise.js b/exercises/F-strings-methods/exercise.js
index 2cffa6a81..0dcab2887 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 message = " tell me how many words I am; ";
+let stringLength = message.length;
+console.log(message + "the length is: " + stringLength);
diff --git a/exercises/F-strings-methods/exercise2.js b/exercises/F-strings-methods/exercise2.js
index b4b46943d..cc4bb7d86 100644
--- a/exercises/F-strings-methods/exercise2.js
+++ b/exercises/F-strings-methods/exercise2.js
@@ -1,3 +1,6 @@
-const name = " Daniel  ";
+const myname = "Karla";
 
-console.log(message);
+let CharactersLength = myname.length;
+
+
+console.log(`my name is ${CharactersLength} characters`); //to make the interpolation is alwais the backticks 
diff --git a/exercises/G-numbers/README.md b/exercises/G-numbers/README.md
index 6775ad18f..dbe5ef4b5 100644
--- a/exercises/G-numbers/README.md
+++ b/exercises/G-numbers/README.md
@@ -10,13 +10,14 @@ You can use mathematical operators to caclulate numbers:
 
 ```js
 var sum = 10 + 2; // 12
-var product = 10 * 2; // 20
+var product = 10 * 2; // 20  
 var quotient = 10 / 2; // 5
 var difference = 10 - 2; // 8
 ```
 
 ## Exercise
 
+
 - Create two variables `numberOfStudents` and `numberOfMentors`
 - Log a message that displays the total number of students and mentors
 
diff --git a/exercises/G-numbers/exercise.js b/exercises/G-numbers/exercise.js
index 49e7bc00b..e58751311 100644
--- a/exercises/G-numbers/exercise.js
+++ b/exercises/G-numbers/exercise.js
@@ -1 +1,9 @@
-// Start by creating a variables `numberOfStudents` and `numberOfMentors`
+// Start by creating a variables
+// `numberOfStudents` and `numberOfMentors`
+
+let numberOfStudents = 15;
+let numberOfMentors = 8;
+
+let total = numberOfStudents + numberOfMentors;
+
+console.log(`total number of studentes and mentor:  ${total}`);
\ No newline at end of file
diff --git a/exercises/I-floats/README.md b/exercises/I-floats/README.md
index bbc9e29c2..093190a4b 100644
--- a/exercises/I-floats/README.md
+++ b/exercises/I-floats/README.md
@@ -1,8 +1,8 @@
 Numbers can be integers (whole numbers) or floats (numbers with a decimal).
 
 ```js
-var preciseAge = 30.612437;
-```
+var preciseAge = 30.612437; //float number
+``` 
 
 Floats can be rounded to the nearest whole number using the `Math.round` function:
 
diff --git a/exercises/I-floats/exercise.js b/exercises/I-floats/exercise.js
index a5bbcd852..5f2bff255 100644
--- a/exercises/I-floats/exercise.js
+++ b/exercises/I-floats/exercise.js
@@ -1,2 +1,13 @@
-var numberOfStudents = 15;
-var numberOfMentors = 8;
+let numberOfStudents = 15;
+let numberOfMentors = 8;
+
+let total = numberOfStudents + numberOfMentors;
+
+console.log(`total number of studentes and mentor:  ${total}`);
+
+let porcentage = (numberOfStudents/total ) * 100; //here we did the average and the number return float
+let porcentageB = (numberOfMentors/total ) * 100;
+
+console.log(`Porcentage students ${Math.round(porcentage)}%`);// here we use the comand Math.round to make it again integer and we added %
+
+console.log(`Porcentage Mentors ${Math.round(porcentageB)}%`);
diff --git a/exercises/K-functions-parameters/exercise.js b/exercises/K-functions-parameters/exercise.js
index 8d5db5e69..962269212 100644
--- a/exercises/K-functions-parameters/exercise.js
+++ b/exercises/K-functions-parameters/exercise.js
@@ -1,8 +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);
 
diff --git a/exercises/K-functions-parameters/exercise2.js b/exercises/K-functions-parameters/exercise2.js
index db7a8904b..358929754 100644
--- a/exercises/K-functions-parameters/exercise2.js
+++ b/exercises/K-functions-parameters/exercise2.js
@@ -1,4 +1,7 @@
 // Declare your function first
+function divide(a, b){
+    return a/b;
+}
 
 var result = divide(3, 4);
 
diff --git a/exercises/K-functions-parameters/exercise3.js b/exercises/K-functions-parameters/exercise3.js
index 537e9f4ec..9528c26c6 100644
--- a/exercises/K-functions-parameters/exercise3.js
+++ b/exercises/K-functions-parameters/exercise3.js
@@ -1,4 +1,7 @@
 // Write your function here
+function createGreeting(a){
+    return "hell, my name is " + a;
+}
 
 var greeting = createGreeting("Daniel");
 
diff --git a/exercises/K-functions-parameters/exercise4.js b/exercises/K-functions-parameters/exercise4.js
index 7ab44589e..60a22ee17 100644
--- a/exercises/K-functions-parameters/exercise4.js
+++ b/exercises/K-functions-parameters/exercise4.js
@@ -1,5 +1,9 @@
 // Declare your function first
+function totalSum(a, b){
+    return a + b;
 
+}
 // Call the function and assign to a variable `sum`
+let sum = totalSum(13, 124);
 
 console.log(sum);
diff --git a/exercises/K-functions-parameters/exercise5.js b/exercises/K-functions-parameters/exercise5.js
index 7c5bcd605..fdacc4688 100644
--- a/exercises/K-functions-parameters/exercise5.js
+++ b/exercises/K-functions-parameters/exercise5.js
@@ -1,4 +1,7 @@
 // Declare your function here
+function createLongGreeting(a, b){
+    return `hello, my name is ${a} and I'm ${b} year old`;
+}
 
 const greeting = createLongGreeting("Daniel", 30);
 
diff --git a/exercises/L-functions-nested/exercise.js b/exercises/L-functions-nested/exercise.js
index a5d377442..998eb8cd7 100644
--- a/exercises/L-functions-nested/exercise.js
+++ b/exercises/L-functions-nested/exercise.js
@@ -3,3 +3,18 @@ var mentor2 = "Irina";
 var mentor3 = "Mimi";
 var mentor4 = "Rob";
 var mentor5 = "Yohannes";
+
+
+function convertNameToUpperCase(name) {
+    return name.toUpperCase();
+}
+
+function createGreeting(name) {
+    return `HELLO ${convertNameToUpperCase(name)}`;
+}
+
+console.log(createGreeting(mentor1));
+console.log(createGreeting(mentor2));
+console.log(createGreeting(mentor3));
+console.log(createGreeting(mentor4));
+console.log(createGreeting(mentor5));
\ No newline at end of file
diff --git a/mandatory/1-syntax-errors.js b/mandatory/1-syntax-errors.js
index a10cc9ac2..67a4ef3da 100644
--- a/mandatory/1-syntax-errors.js
+++ b/mandatory/1-syntax-errors.js
@@ -1,18 +1,22 @@
 // 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;
 
-  return "The total is total";
+function getTotal(a, b){
+  let total = a + b;
+  return `The total is ${total}`;  //this line we combin
+
 }
 
+
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====
diff --git a/mandatory/2-logic-error.js b/mandatory/2-logic-error.js
index 9cca7603b..c0472ecb0 100644
--- a/mandatory/2-logic-error.js
+++ b/mandatory/2-logic-error.js
@@ -1,16 +1,26 @@
 // The syntax for this function is valid but it has an error, find it and fix it.
 
-function trimWord(word) {
-  return wordtrim();
+//in this exercise we use the mothod .trim() which help to eliminate leading and trailing spaces. 
+ 
+function trimWord(phrase) {
+  let string = phrase.trim(); 
+  return string;
 }
 
-function getStringLength(word) {
-  return "word".length();
+// the function .length will show the number of the string that we give by the parameter a
+// we created a local variable where we store the result of the parameter 
+
+function getStringLength(a) {
+  let total = a.length;
+  return total;
 }
 
+
+//we declared a variable total to store the  math operation then we sent the result in the return;
+
 function multiply(a, b, c) {
-  a * b * c;
-  return;
+  let total = a * b * c;
+  return total;
 }
 
 /* 
diff --git a/mandatory/3-function-output.js b/mandatory/3-function-output.js
index 5a953ba60..97f8ebc88 100644
--- a/mandatory/3-function-output.js
+++ b/mandatory/3-function-output.js
@@ -1,16 +1,24 @@
 // Add comments to explain what this function does. You're meant to use Google!
+
+
+// this function generate a ramdom number between 0 to one number less than the maximun
+// which we sent in the parametre. so we wil get from 0 to 9
 function getRandomNumber() {
-  return Math.random() * 10;
+  return Math.random( ) * 10;
 }
+// console.log(getRandomNumber(10))
 
 // Add comments to explain what this function does. You're meant to use Google!
+//This function will combine two parametres in the same line
 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.
+// 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);
+  //we create the spaces that required with the " " and .concat help to join the parametres
 }
 
 /* 
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index ba77c7ae2..7f7d068b9 100644
--- a/mandatory/4-tax.js
+++ b/mandatory/4-tax.js
@@ -5,9 +5,15 @@
   Sales tax is 20% of the price of the product.
 */
 
-function calculateSalesTax() {}
+function calculateSalesTax(price) {
+  let porcentage = price * 0.20; //we multiply with 0.20 to obtain the porcentage which
+  //will be included in the final price.
+  porcentage += price;
+  return porcentage;
+}
 
-/*
+
+/* 
   CURRENCY FORMATTING
   ===================
   The business has informed you that prices must have 2 decimal places
@@ -16,9 +22,14 @@ function calculateSalesTax() {}
 
   Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
 */
+// let calculateSalestax = calculateSalestax;
 
-function addTaxAndFormatCurrency() {}
-
+function addTaxAndFormatCurrency(price) {
+  let finalPrice = `£${calculateSalesTax(price).toFixed(2)}`;
+  //we create a new variable and call the previus function and concatenate with £ and
+  // .toFixed will give us 2 digits to appear after the decimal point.
+  return finalPrice;
+}
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====
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"
+        ]
       }
     ]
   },