diff --git a/1-exercises/A-undefined/demo.js b/1-exercises/A-undefined/demo.js
new file mode 100644
index 00000000..79be4cc5
--- /dev/null
+++ b/1-exercises/A-undefined/demo.js
@@ -0,0 +1,116 @@
+function double(n) {
+    return n * 2;
+}
+console.log(double(3)); 
+console.log(double(5));
+
+
+function doubleEachElement(arr) {
+    let newArr = [];
+    for(let element of arr) {
+        let newValue = double(element);
+        newArr.push(newValue);
+    }
+    return newArr;    
+}
+
+
+function triple(n) {
+    return n * 3;
+}
+console.log(double(3)); 
+console.log(double(5));
+
+function tripleEachElement(arr) {
+    let newArr = [];
+    for(let element of arr) {
+        let newValue = triple(element);
+        newArr.push(newValue);
+    }
+    return newArr;    
+}
+
+
+function update(arr, func) {
+    let newArr = [];
+    for(let element of arr) {
+        let newValue = func(element);
+        newArr.push(newValue);
+    }
+    return newArr;    
+}
+let arr =[2, 3, 4];
+let doublesValues = update(arr, double);
+let tripleValues = update(arr, triple);
+console.log(doublesValues);
+console.log(tripleValues);
+
+function double(n) {
+    return n * 2;
+}
+update(arr, double);
+
+function hello(teamMember) {
+    console.log("Hello " + teamMember);
+}
+function notifyPeople(team) {
+    for(teamMember of team) {
+        hello(teamMember);
+    }
+}
+
+notifyPeople(arr, hello)
+
+
+function goodBye(teamMember) {
+    console.log('Goodbye ' + teamMember);
+}
+    function notifyPeople(team, func ){
+        for(teamMember of team) {
+           func(teamMember);
+     
+        }
+    }
+
+notifyPeople(arr, goodBye);
+
+
+let shoppingList = ['bananas', 'milk', 'bread'];
+shoppingList.forEach(value => {
+    console.log(`We need to buy ${value}`);
+});
+
+let data = [1, 2, 3, 4, 5];
+let newArr = data.map(value =>  value * 2); 
+
+
+console.log(newArr);
+console.log(data);
+
+
+let data1 = [1, 2, 3, 4, 5];
+let evenNumbers = data.filter(value => {
+    return value % 2 === 0});
+console.log(evenNumbers);
+console.log(data1);
+
+let data2 = [1, 2, 3, 4, 5];
+let firstEvenNumber = data.find(value => value % 2 === 0);
+console.log(firstEvenNumber); 
+
+let data3 = [1, 2, 3, 4, 5];
+data
+    .filter(value => value % 2 === 0)
+    .map(value => value * 3)
+    .forEach(value => console.log(value));
+
+
+
+    let channels = ["bbc1", "BBC2", "ITV", "channel4", 
+"Channel5", "bbc3", "bbc4", "itv2", "ITV3", "itv4"];
+console.log(channels);
+
+channels.map(channel => channel.toUpperCase)
+let newChannel = channels.map(item => item.toUpperCase());
+let itvChannel = newChannel.filter(item => item.includes('ITV'))
+newChannel.forEach(item => console.log(item));
diff --git a/1-exercises/A-undefined/exercise.js b/1-exercises/A-undefined/exercise.js
index 0acfc78d..f1806fc6 100644
--- a/1-exercises/A-undefined/exercise.js
+++ b/1-exercises/A-undefined/exercise.js
@@ -1,36 +1,192 @@
-/*
-    By now, you would have already seen "undefined", either in an error message or being output from your program.
-    But what does it mean? undefined represents the absence of a value.
+// /*
+//     By now, you would have already seen "undefined", either in an error message or being output from your program.
+//     But what does it mean? undefined represents the absence of a value.
     
-    In some cases, undefined will be used by a programmer intentionally, and they will write code to handle it.
-    But usually, when you see undefined - it means something has gone wrong!
+//     In some cases, undefined will be used by a programmer intentionally, and they will write code to handle it.
+//     But usually, when you see undefined - it means something has gone wrong!
 
-    Below are 4 typical examples of when you would see undefined.
-    For each example, can you explain why we are seeing undefined?
-*/
+//     Below are 4 typical examples of when you would see undefined.
+//     For each example, can you explain why we are seeing undefined?
+// */
 
-// Example 1
-let a;
-console.log(a);
+// // Example 1
+// let a;
+// console.log(a);
+// //does not have assigned value//
 
 
-// Example 2
-function sayHello() {
-    let message = "Hello";
+// // Example 2
+// function sayHello() {
+//     let message = "Hello";
+// }
+
+// let hello = sayHello();
+// console.log(hello);
+// //a value was not returned//
+
+// // Example 3
+// function sayHelloToUser(user) {
+//     console.log(`Hello ${user}`);
+// }
+
+// sayHelloToUser();
+// //there is no any parameter when sayHelloToUser() is called//
+
+// // Example 4
+// let arr = [1,2,3];
+// console.log(arr[3]);
+// //there is no value in arr[3]//
+
+
+
+// let i = 0;
+// while (i < 3) {
+//     console.log(i);
+           // i++
+// }
+
+function sumTo(n) {
+    let sum = 0;
+    let i = 0;
+ while(i <= n) {
+    sum = sum + i;
+    i = i + 1;
+ }   
+ return sum;
+ 
+}
+console.log(sumTo(3));
+
+
+function showStocks(stocks){
+    if(stocks.lengths === 0) {
+        console.log("Empty Portfolio");
+    } else {
+    let i = 1;
+while (i <= stocks.length) {
+    console.log(stocks[i - 1]);
+    i++;
+}
+}
+}
+let stocks = ["aapl","msft","amzn","googl", 
+"tsla"]
+showStocks(stocks);
+
+
+for(let i = 0; i < 3; i++) {
+    console.log(i);
 }
 
-let hello = sayHello();
-console.log(hello);
 
 
-// Example 3
-function sayHelloToUser(user) {
-    console.log(`Hello ${user}`);
+function sumTo(n) {
+    let sum = 0;
+ for( let i = 0; i <= n; i = i + 1) {
+    sum = sum + i;
+   
+ }   
+ return sum;
+ 
+}
+function showStocks(stocks){
+    if(stocks.lengths === 0) {
+        console.log("Empty Portfolio");
+    } else {
+for(let i = 0; i < stocks.length; i++) {
+    console.log(stocks[i]);
+    
 }
+}
+}
+stocks = ["aapl","msft","amzn","googl", 
+"tsla"]
+showStocks(stocks);
+
 
-sayHelloToUser();
+let colours = ["red", "green", "blue"];
 
+ for(let i = 0; i < colours.length; i++) {
+    let colour = colours[i];
+    console.log(colour);
+ }
+
+
+ let colors = ["red", "green", "blue"];
+for(let color of colors) {
+    console.log(color);
+}
 
-// Example 4
-let arr = [1,2,3];
-console.log(arr[3]);
+let phrase = "CodeYourFuture";
+for(let letter of phrase) {
+    console.log(letter);
+}
+
+
+function calculatechanges(prices) {
+    let change = prices[prices.length - 1] - prices[0];
+    return change.toFixed(2);
+}
+function changeInPrices(closingPrices){
+    let changes = [];
+
+   for(let pricesForOneStock of closingPrices) {
+    let change = calculatechanges(pricesForOneStock);
+   changes.push(change);
+}
+return changes;
+}
+    
+const closingPricesLast5Days = [
+  [179.19, 180.33, 176.28, 175.64, 172.99], // AAPL
+  [340.69, 342.45, 334.69, 333.20, 327.29], // MSFT
+  [3384.44, 3393.39, 3421.37, 3420.74, 3408.34], // AMZN
+  [2951.88, 2958.13, 2938.33, 2928.30, 2869.45], // GOOGL
+  [1101.30, 1093.94, 1067.00, 1008.87, 938.53] // TSLA
+];
+let result = changeInPrices(closingPricesLast5Days);
+console.log(result);
+
+
+let fruits = ["orange", "apple", "banana"];
+fruits.splice(1, 2, "pear");
+console.log(fruits);  
+console.log(fruits.length)
+
+
+ let todo = ["order dog food", "do the dishes"];
+ todo.splice(1, 1, 'take out garbage');
+
+console.log(fruits);
+
+console.log(["orange", "apple", "banana"].sort());
+
+
+let array = [1, 2, 3];
+let firstNewArr = array.concat(4, 5, 6);
+let secondNewArr = array.concat([4, 5, 6]);
+console.log(firstNewArr);
+console.log(secondNewArr);
+console.log(array);
+
+
+let arr = [1, 2, 3, 4, 5];
+console.log(arr.slice(0, 3));  
+console.log(arr.slice(3));  
+console.log(arr.slice(1, -1));  
+console.log(arr);  
+
+let arra = [1, 3, 5];
+console.log(arra.includes(2));
+console.log(arra.includes(3));
+
+let arry = ["orange", "apple", "banana"];
+console.log(arry.join());
+console.log(arry.join(' - '));
+
+let names = ['khadija', 'tom'];
+console.log(names.join());
+
+function namesInArray(names) {
+    
+}
\ No newline at end of file
diff --git a/1-exercises/B-while-loop/exercise.js b/1-exercises/B-while-loop/exercise.js
index b459888f..def9e376 100644
--- a/1-exercises/B-while-loop/exercise.js
+++ b/1-exercises/B-while-loop/exercise.js
@@ -1,12 +1,20 @@
 /*
-    while loops can be useful when you want to execute some code as long as some condition is true.    
+    while loops can be useful when you want to execute some code as long as 
+    some condition is true.    
 
-    Using a while loop, complete the function below so it logs (using console.log) the first n even numbers as a comma-seperated string.
+    Using a while loop, complete the function below so it logs (using console.log) 
+    the first n even numbers as a comma-seperated string.
     The list of numbers should start with 0. n is being passed in as a parameter.
 */
 
 function evenNumbers(n) {
-    // TODO
+  let result = [];
+  let i = 0;
+  while (i < n ) {
+    result.push(i * 2);
+    i++;
+  }
+  console.log(result.join());
 }
 
 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..5270f8d4 100644
--- a/1-exercises/C-while-loop-with-array/exercise.js
+++ b/1-exercises/C-while-loop-with-array/exercise.js
@@ -17,7 +17,15 @@ const BIRTHDAYS = [
 ];
 
 function findFirstJulyBDay(birthdays) {
-    // TODO
+    let currentIndex = 0;
+while (currentIndex < birthdays.length) {
+if (birthdays[currentIndex].includes('July')) {
+
+     return birthdays[currentIndex];
+    
+   }
+   currentIndex++;
 }
 
+}
 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..4fa5cf3a 100644
--- a/1-exercises/D-do-while/exercise.js
+++ b/1-exercises/D-do-while/exercise.js
@@ -7,8 +7,18 @@
 */
 
 function evenNumbersSum(n) {
-    // TODO
-}
+    let sum = 0;
+let i = 0;
+        do{
+            sum += (i * 2);
+            i++;
+        } while (i < n );
+    
+        return sum;
+
+    }
+
+
 
 console.log(evenNumbersSum(3)); // should output 6
 console.log(evenNumbersSum(0)); // should output 0
diff --git a/1-exercises/E-for-loop/exercise1.js b/1-exercises/E-for-loop/exercise1.js
index db5fac64..cd5e1347 100644
--- a/1-exercises/E-for-loop/exercise1.js
+++ b/1-exercises/E-for-loop/exercise1.js
@@ -3,12 +3,15 @@
 
     Change the while loop below into a for loop.
 */
-
-
-// Change the below code to use a for loop instead of a while loop.
 let i = 0;
-while(i < 26) {
+while (i < 26) {
     console.log(String.fromCharCode(97 + i));
     i++;
 }
+
+// Change the below code to use a for loop instead of a while loop.
+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..0b373287 100644
--- a/1-exercises/E-for-loop/exercise2.js
+++ b/1-exercises/E-for-loop/exercise2.js
@@ -28,6 +28,10 @@ const AGES = [
 
 // TODO - Write for loop code here
 
+
+for (let i = 0; i < WRITERS.length; i++) {
+    console.log(`${WRITERS[i]} is ${AGES[i]} years old`);
+}
 /*
 The output should look something like this:
 
@@ -36,4 +40,4 @@ Zadie Smith is 40 years old
 Jane Austen is 41 years old
 Bell Hooks is 63 years old
 Yukiko Motoya is 49 years old
-*/
+*/ 
diff --git a/1-exercises/F-for-of-loop/exercise.js b/1-exercises/F-for-of-loop/exercise.js
index 65585c6a..4eac410b 100644
--- a/1-exercises/F-for-of-loop/exercise.js
+++ b/1-exercises/F-for-of-loop/exercise.js
@@ -10,7 +10,13 @@ let tubeStations = [
     "Oxford Street",
     "Tottenham Court Road"
 ];
-
+for (let station of tubeStations) {
+    console.log(station)
+}
 
 // TODO Use a for-of loop to capitalise and output each letter in the string seperately.
 let str = "codeyourfuture";
+for ( let s of str) {
+    console.log(s.toUpperCase())
+    
+}
diff --git a/2-mandatory/1-weather-report.js b/2-mandatory/1-weather-report.js
index dcc2bdb0..9a894474 100644
--- a/2-mandatory/1-weather-report.js
+++ b/2-mandatory/1-weather-report.js
@@ -12,7 +12,12 @@
 */
 
 function getTemperatureReport(cities) {
-    // TODO
+    let arr=[];    
+    for (let city of cities)  {     
+         arr.push(`The temperature in ${city} is ${temperatureService(city)} degrees`);
+
+    }
+    return arr;
 }
 
 
@@ -39,7 +44,7 @@ test("should return a temperature report for the user's cities", () => {
         "São Paulo"
     ]
 
-    expect(getTemperatureReport(usersCities)).toEqual([
+    expect(getTemperatureReport(usersCities)). toEqual([
         "The temperature in London is 10 degrees",
         "The temperature in Paris is 12 degrees",
         "The temperature in São Paulo is 23 degrees"
diff --git a/2-mandatory/2-retrying-random-numbers.js b/2-mandatory/2-retrying-random-numbers.js
index 10aab37d..6b314ac6 100644
--- a/2-mandatory/2-retrying-random-numbers.js
+++ b/2-mandatory/2-retrying-random-numbers.js
@@ -10,8 +10,14 @@ function generateRandomNumber() {
 }
 
 function getRandomNumberGreaterThan50() {
-    // TODO - implement using a do-while loop
-}
+   let  generatedNumber;
+   
+   do {
+  generatedNumber = generateRandomNumber();
+   } while (generatedNumber <= 50);
+   return generatedNumber;
+   } 
+console.log(getRandomNumberGreaterThan50());
 
 /* ======= TESTS - DO NOT MODIFY ===== */
 
diff --git a/2-mandatory/3-financial-times.js b/2-mandatory/3-financial-times.js
index 2ce6fb73..2d9a2549 100644
--- a/2-mandatory/3-financial-times.js
+++ b/2-mandatory/3-financial-times.js
@@ -5,7 +5,13 @@
     Implement the function below, which will return a new array containing only article titles which will fit.
 */
 function potentialHeadlines(allArticleTitles) {
-    // TODO
+ let arr =[];
+    for (let article of allArticleTitles){
+        if (article.length <= 65){
+            arr.push(article)
+        }
+    }
+    return arr;
 }
 
 /*
@@ -14,16 +20,34 @@ function potentialHeadlines(allArticleTitles) {
     (you can assume words will always be seperated by a space)
 */
 function titleWithFewestWords(allArticleTitles) {
-    // TODO
+    let arr = [];
+    for (let i = 0; i < allArticleTitles.length; i++) {
+        arr.push(allArticleTitles[i].split(" ").length);
+    }
+    return allArticleTitles[arr.indexOf(Math.min(...arr))];
 }
 
-/*
-    The editor of the FT has realised that headlines which have numbers in them get more clicks!
-    Implement the function below to return a new array containing all the headlines which contain a number.
+function numberOfWords(title) {
+    return title.split('').length;
+}
+/*let 
+   on The editor of the FT has realised that headlines which have numbers in them get more clicks!
+    Implement the function below to return a new array containing all the headlines which ctain a number.
     (Hint: remember that you can also loop through the characters of a string if you need to)
 */
 function headlinesWithNumbers(allArticleTitles) {
     // TODO
+    let arr= [];
+    for (let article of allArticleTitles){
+        for (let char of article){
+            if (char>="0" && char<="9"){
+                arr.push (article);
+                break;
+            }
+
+        }
+    }
+    return arr
 }
 
 /*
@@ -32,6 +56,13 @@ function headlinesWithNumbers(allArticleTitles) {
 */
 function averageNumberOfCharacters(allArticleTitles) {
     // TODO
+    let sum = 0; 
+    for (let article of allArticleTitles){
+        sum += article.length;
+
+        }
+    
+    return Math.round(sum / allArticleTitles.length)
 }
 
 
diff --git a/2-mandatory/4-stocks.js b/2-mandatory/4-stocks.js
index 72d62f94..1bdd97ce 100644
--- a/2-mandatory/4-stocks.js
+++ b/2-mandatory/4-stocks.js
@@ -34,10 +34,20 @@ const CLOSING_PRICES_LAST_5_DAYS_FOR_ALL_STOCKS = [
         Functions can help with this!
 */
 function getAveragePrices(closingPricesForAllStocks) {
-    // TODO
+let totalArray = [];
+for (let stockClosingPrices of closingPricesForAllStocks) {
+    let stockTotal = 0;
+    for(let stockClosingPrice of stockClosingPrices) {
+        stockTotal = stockClosingPrice + stockTotal;
+    }
+    let stockAverage = stockTotal / stockClosingPrices.length;
+    totalArray.push(Number(stockAverage.toFixed(2)));
+}
+return totalArray;
 }
 
-/*
+
+    /*
     We also want to see what the change in price is from the first day to the last day for each stock.
     Implement the below function, which
         - Takes this CLOSING_PRICES_LAST_5_DAYS_FOR_ALL_STOCKS array as input (remember, it's an array of arrays)
@@ -48,7 +58,14 @@ function getAveragePrices(closingPricesForAllStocks) {
     The price change value should be rounded to 2 decimal places, and should be a number (not a string)
 */
 function getPriceChanges(closingPricesForAllStocks) {
-    // TODO
+    let differenceArray = [];
+    for(let item of closingPricesForAllStocks) {
+        let firstDayPrice = item[0];
+        let lastDayPrice = item[item.length-1];
+        let difference = lastDayPrice - firstDayPrice;
+        differenceArray.push(Number(difference.toFixed(2)));
+    }
+    return differenceArray;
 }
 
 /*
@@ -64,9 +81,13 @@ function getPriceChanges(closingPricesForAllStocks) {
     The price should be shown with exactly 2 decimal places.
 */
 function highestPriceDescriptions(closingPricesForAllStocks, stocks) {
-    // TODO
-}
+     let arr=[];
+    for (let i=0;i<closingPricesForAllStocks.length;i++){
+        arr.push (`The highest price of ${stocks[i].toUpperCase()} in the last 5 days was ${(Math.max(...closingPricesForAllStocks[i])).toFixed(2)}`)
+    }
+    return arr;
 
+}
 
 /* ======= TESTS - DO NOT MODIFY ===== */
 test("should return the average price for each stock", () => {
diff --git a/3-extra/1-factorial.js b/3-extra/1-factorial.js
index 31f8052c..0a3997aa 100644
--- a/3-extra/1-factorial.js
+++ b/3-extra/1-factorial.js
@@ -10,6 +10,13 @@
 
 function factorial(input) {
     // TODO
+    let i = 1;
+    let multy = 1;
+    while(i <= input) {
+        multy *= i;
+        i++;
+    }
+    return multy;
 }
 
 /* ======= TESTS - DO NOT MODIFY ===== */
diff --git a/3-extra/2-array-of-objects.js b/3-extra/2-array-of-objects.js
index ee57960f..98a5395d 100644
--- a/3-extra/2-array-of-objects.js
+++ b/3-extra/2-array-of-objects.js
@@ -12,7 +12,22 @@
 
 function getHighestRatedInEachGenre(books) {
     // TODO
+
+     let output = [];
+
+    let genres = Array.from(new Set(books.map(element => element.genre)));
+
+    for (let genre in genres) {   
+        let result = books
+                        .filter(element => element.genre === genres[genre])
+                        .reduce((pV, cV) => pV.rating < cV.rating ? cV : pV);
+
+        output.push(result.title);
+    }
+
+    return output;
 }
+   
 
 
 /* ======= Book data - DO NOT MODIFY ===== */
diff --git a/3-extra/3-fibonacci.js b/3-extra/3-fibonacci.js
index 9ef9aec7..9537e227 100644
--- a/3-extra/3-fibonacci.js
+++ b/3-extra/3-fibonacci.js
@@ -15,6 +15,11 @@
 
 function generateFibonacciSequence(n) {
     // TODO
+    let arr = [0, 1];
+   for (let i = 0; i < n - 2; i++) {
+arr.push (arr[i] + arr[i + 1]);
+    }
+    return arr;
 }
 
 /* ======= TESTS - DO NOT MODIFY ===== */