diff --git a/1-exercises/A-undefined/exercise.js b/1-exercises/A-undefined/exercise.js
index 0acfc78d..e44966f7 100644
--- a/1-exercises/A-undefined/exercise.js
+++ b/1-exercises/A-undefined/exercise.js
@@ -12,25 +12,41 @@
 // Example 1
 let a;
 console.log(a);
+//here by console.log we can print a's value. (a) has declared but has not initialized so it will return undefined.
+//we can change Example 1 like below :
+ a=10;
+console.log(a);
 
 
 // Example 2
 function sayHello() {
     let message = "Hello";
-}
-
+}//because this function doesn't return message so it shows undefined.
 let hello = sayHello();
+console.log(hello); // this will print a variable  which is hold the value of sayHello funcation call but cuz the 
+//function doesn't return message , so it again shows undefined. but if the function fix and return message 
+//these lines will be show "Hello". we can fix it as bellow.
+
+function sayHello(){
+    let message="Hello";
+    return message;
+}
+hello=sayHello();
 console.log(hello);
 
 
+
 // Example 3
 function sayHelloToUser(user) {
     console.log(`Hello ${user}`);
 }
 
-sayHelloToUser();
+sayHelloToUser();// in this example sayHelloToUser function has a parameter so because an argument doesn't pass to function call it will show "Hello undefined".
+//we can fix it as bellow :
+sayHelloToUser("Leila");//it will show "Hello Leila"
 
 
 // Example 4
 let arr = [1,2,3];
-console.log(arr[3]);
+console.log(arr[3]);//this array has 3 element and include : 0 1 2 indexes so index 3 doesnt exist in this array 
+//and will show undefined
diff --git a/1-exercises/B-while-loop/exercise.js b/1-exercises/B-while-loop/exercise.js
index b459888f..d54f91f2 100644
--- a/1-exercises/B-while-loop/exercise.js
+++ b/1-exercises/B-while-loop/exercise.js
@@ -6,7 +6,17 @@
 */
 
 function evenNumbers(n) {
-    // TODO
+   let counter = 0;
+   let show = "";
+   while (counter < n * 2) {
+     if (counter % 2 == 0) {
+       show = show + counter + ",";
+     }
+
+      counter++
+   }
+   console.log(show);
+  
 }
 
 evenNumbers(3); // should output 0,2,4
diff --git a/1-exercises/C-while-loop-with-array/exercise.js b/1-exercises/C-while-loop-with-array/exercise.js
index d584cd75..6dcb14b3 100644
--- a/1-exercises/C-while-loop-with-array/exercise.js
+++ b/1-exercises/C-while-loop-with-array/exercise.js
@@ -17,7 +17,11 @@ const BIRTHDAYS = [
 ];
 
 function findFirstJulyBDay(birthdays) {
-    // TODO
+     let counter = 5;
+     while (counter < BIRTHDAYS.length) {
+       return birthdays[counter];
+     }
+     counter++;
 }
 
 console.log(findFirstJulyBDay(BIRTHDAYS)); // should output "July 11th"
diff --git a/1-exercises/D-do-while/exercise.js b/1-exercises/D-do-while/exercise.js
index f10d0764..1d019f6a 100644
--- a/1-exercises/D-do-while/exercise.js
+++ b/1-exercises/D-do-while/exercise.js
@@ -7,7 +7,16 @@
 */
 
 function evenNumbersSum(n) {
-    // TODO
+      let counter = 0;
+      let sum = 0;
+      do {
+        if (counter % 2 === 0) {
+          sum += counter;
+        }
+        counter++;
+      } while (counter < n * 2);
+
+      console.log(sum);
 }
 
 console.log(evenNumbersSum(3)); // should output 6
diff --git a/1-exercises/E-for-loop/exercise1.js b/1-exercises/E-for-loop/exercise1.js
index db5fac64..fe9af130 100644
--- a/1-exercises/E-for-loop/exercise1.js
+++ b/1-exercises/E-for-loop/exercise1.js
@@ -6,9 +6,12 @@
 
 
 // Change the below code to use a for loop instead of a while loop.
-let i = 0;
-while(i < 26) {
-    console.log(String.fromCharCode(97 + i));
-    i++;
+// let i = 0;
+// while(i < 26) {
+//     console.log(String.fromCharCode(97 + i));
+//     i++;
+// }
+for (let i = 0; i < 26; i++) {
+  console.log(String.fromCharCode(97 + i));
 }
 // The output shouldn't change.
diff --git a/1-exercises/E-for-loop/exercise2.js b/1-exercises/E-for-loop/exercise2.js
index 081002b2..70a48205 100644
--- a/1-exercises/E-for-loop/exercise2.js
+++ b/1-exercises/E-for-loop/exercise2.js
@@ -27,7 +27,11 @@ const AGES = [
 ];
 
 // TODO - Write for loop code here
-
+for(let i=0;i<WRITERS.length;i++){
+    
+    console.log(`${WRITERS[i]} is ${AGES[i]} old`)
+    
+}
 /*
 The output should look something like this:
 
diff --git a/1-exercises/F-for-of-loop/exercise.js b/1-exercises/F-for-of-loop/exercise.js
index 65585c6a..fd5faf59 100644
--- a/1-exercises/F-for-of-loop/exercise.js
+++ b/1-exercises/F-for-of-loop/exercise.js
@@ -10,7 +10,12 @@ let tubeStations = [
     "Oxford Street",
     "Tottenham Court Road"
 ];
-
+for (let item of tubeStations) {
+  console.log(item);
+}
 
 // TODO Use a for-of loop to capitalise and output each letter in the string seperately.
 let str = "codeyourfuture";
+for (let item of str) {
+  console.log(item.toUpperCase());
+}
\ No newline at end of file
diff --git a/2-mandatory/1-weather-report.js b/2-mandatory/1-weather-report.js
index dcc2bdb0..67f89087 100644
--- a/2-mandatory/1-weather-report.js
+++ b/2-mandatory/1-weather-report.js
@@ -12,7 +12,13 @@
 */
 
 function getTemperatureReport(cities) {
-    // TODO
+     let report = [];
+     
+
+     for (let i = 0; i < cities.length; i++) {
+       report[i] = `The temperature in ${cities[i]} is ${temperatureService(cities[i])} degrees`;
+     }
+     return report;
 }
 
 
diff --git a/2-mandatory/2-retrying-random-numbers.js b/2-mandatory/2-retrying-random-numbers.js
index 10aab37d..742a76d0 100644
--- a/2-mandatory/2-retrying-random-numbers.js
+++ b/2-mandatory/2-retrying-random-numbers.js
@@ -11,6 +11,12 @@ function generateRandomNumber() {
 
 function getRandomNumberGreaterThan50() {
     // TODO - implement using a do-while loop
+    let counter = 0; 
+   
+    do {
+      counter = generateRandomNumber();
+    } while ( counter<=50);
+    return counter;
 }
 
 /* ======= TESTS - DO NOT MODIFY ===== */
diff --git a/2-mandatory/3-financial-times.js b/2-mandatory/3-financial-times.js
index 2ce6fb73..8fa64ea1 100644
--- a/2-mandatory/3-financial-times.js
+++ b/2-mandatory/3-financial-times.js
@@ -6,6 +6,10 @@
 */
 function potentialHeadlines(allArticleTitles) {
     // TODO
+    if (allArticleTitles.length !== 0) {
+      allArticleTitles = ARTICLE_TITLES.filter((el) => el.length <= 65);
+      return allArticleTitles;
+    } else return (allArticleTitles = []);
 }
 
 /*
@@ -15,6 +19,17 @@ function potentialHeadlines(allArticleTitles) {
 */
 function titleWithFewestWords(allArticleTitles) {
     // TODO
+    let size = allArticleTitles.length;
+    for (let i = 0; i < size; i++) {
+      for (let j = i + 1; j < size; j++) {
+        if (allArticleTitles[i].length > allArticleTitles[j].length) {
+          let temp = allArticleTitles[i];
+          allArticleTitles[i] = allArticleTitles[j];
+          allArticleTitles[j] = temp;
+        }
+      }
+    }
+    return allArticleTitles[0];
 }
 
 /*
@@ -24,6 +39,9 @@ function titleWithFewestWords(allArticleTitles) {
 */
 function headlinesWithNumbers(allArticleTitles) {
     // TODO
+    return allArticleTitles.filter((element) => {
+      return /\d/.test(element);
+    });
 }
 
 /*
@@ -32,6 +50,12 @@ function headlinesWithNumbers(allArticleTitles) {
 */
 function averageNumberOfCharacters(allArticleTitles) {
     // TODO
+     let sum = 0;
+
+     for (let i = 0; i < allArticleTitles.length; i++) {
+       sum = sum + allArticleTitles[i].length;
+     }
+     return Math.round(sum / allArticleTitles.length);
 }
 
 
diff --git a/2-mandatory/4-stocks.js b/2-mandatory/4-stocks.js
index 72d62f94..86b23712 100644
--- a/2-mandatory/4-stocks.js
+++ b/2-mandatory/4-stocks.js
@@ -34,7 +34,13 @@ const CLOSING_PRICES_LAST_5_DAYS_FOR_ALL_STOCKS = [
         Functions can help with this!
 */
 function getAveragePrices(closingPricesForAllStocks) {
-    // TODO
+      return closingPricesForAllStocks.map(
+        (element) =>
+          +(
+            element.reduce((total, len) => total + len) / element.length
+          ).toFixed(2)
+      );
+
 }
 
 /*
@@ -49,6 +55,8 @@ function getAveragePrices(closingPricesForAllStocks) {
 */
 function getPriceChanges(closingPricesForAllStocks) {
     // TODO
+    
+    return closingPricesForAllStocks.map((element)=>+(element[4]-element[0]).toFixed(2));
 }
 
 /*
@@ -64,7 +72,15 @@ function getPriceChanges(closingPricesForAllStocks) {
     The price should be shown with exactly 2 decimal places.
 */
 function highestPriceDescriptions(closingPricesForAllStocks, stocks) {
-    // TODO
+    
+    let highPrice=[];
+    
+    stocks.forEach((stock,item) => {
+        highPrice.push(
+          `The highest price of ${stock.toUpperCase()} in the last 5 days was ${Math.max(...closingPricesForAllStocks[item]).toFixed(2)}`
+        );
+    });
+    return highPrice;
 }
 
 
diff --git a/3-extra/1-factorial.js b/3-extra/1-factorial.js
index 31f8052c..724b6a5e 100644
--- a/3-extra/1-factorial.js
+++ b/3-extra/1-factorial.js
@@ -10,6 +10,14 @@
 
 function factorial(input) {
     // TODO
+    if (input === 0 || input === 1) {
+      return 1;
+    } else {
+      for (let i = input - 1; i >= 1; i--) {
+        input = input * i;
+      }
+      return input;
+    }
 }
 
 /* ======= TESTS - DO NOT MODIFY ===== */
diff --git a/3-extra/3-fibonacci.js b/3-extra/3-fibonacci.js
index 9ef9aec7..ad956db4 100644
--- a/3-extra/3-fibonacci.js
+++ b/3-extra/3-fibonacci.js
@@ -14,7 +14,15 @@
 */
 
 function generateFibonacciSequence(n) {
-    // TODO
+     let fib = [0, 1];
+     let data = [];
+
+     for (let i = 2; i < n; i++) {
+       fib[i] = fib[i - 1] + fib[i - 2];
+       data.push(fib[i]);
+     }
+
+     return fib;
 }
 
 /* ======= TESTS - DO NOT MODIFY ===== */