diff --git a/extra/1-currency-conversion.js b/extra/1-currency-conversion.js
index 75b3c6aab..71a559d6b 100644
--- a/extra/1-currency-conversion.js
+++ b/extra/1-currency-conversion.js
@@ -5,7 +5,15 @@
   Write a function that converts a price to USD (exchange rate is 1.4 $ to £)
 */
 
-function convertToUSD() {}
+let total = 0.00;
+let gbp = 0.00;
+
+let brl = 0.00;
+
+function convertToUSD(gbp) {
+  let usd = gbp * 1.4; 
+  return usd;
+}
 
 /*
   CURRENCY CONVERSION
@@ -15,7 +23,13 @@ function convertToUSD() {}
   They have also decided that they should add a 1% fee to all foreign transactions, which means you only convert 99% of the £ to BRL.
 */
 
-function convertToBRL() {}
+
+function convertToBRL(gbp) {
+brl = gbp * 0.99 * 5.7 ;
+brl = parseFloat(brl.toFixed(2));
+return brl;
+
+}
 
 /* ======= TESTS - DO NOT MODIFY ===== 
 There are some Tests in this file that will help you work out if your code is working.
diff --git a/extra/2-piping.js b/extra/2-piping.js
index b4f8c4c1b..c7ddb60cf 100644
--- a/extra/2-piping.js
+++ b/extra/2-piping.js
@@ -15,27 +15,35 @@
   3. Write a more readable version of what you wrote in step 2 under the BETTER PRACTICE comment. Assign
   the final result to the variable goodCode
 */
+let num1; 
+let num2; 
 
-function add() {
-
+function add(num1, num2) {
+  return num1 + num2;
 }
 
-function multiply() {
-
+function multiply(num1, num2) {
+  return num1 * num2;
 }
 
-function format() {
-
+function format(num1) {
+  return "£" + num1;
 }
 
 const startingValue = 2;
 
 // Why can this code be seen as bad practice? Comment your answer.
-let badCode =
+let badCode = add(10, startingValue);
+badCode = multiply(2,badCode);
+badCode= format(badCode);
+
 
 /* BETTER PRACTICE */
 
-let goodCode =
+
+let addition = add(10,startingValue);
+let multiplication = multiply(2, addition);
+let goodCode = "£" + multiplication;
 
 /* ======= TESTS - DO NOT MODIFY ===== 
 There are some Tests in this file that will help you work out if your code is working.
diff --git a/extra/3-magic-8-ball.js b/extra/3-magic-8-ball.js
index 46f65f928..3fed6dad3 100644
--- a/extra/3-magic-8-ball.js
+++ b/extra/3-magic-8-ball.js
@@ -1,54 +1,51 @@
-/**
-
-  Let's peer into the future using a Magic 8 Ball!
-  https://en.wikipedia.org/wiki/Magic_8-Ball 
-
-  There are a few steps to being able view the future though:
-  * Ask a question
-  * Shake the ball
-  * Get an answer
-  * Decide if it's positive or negative
-
-  The question can be anything, but the answers are fixed,
-  and have different levels of positivity or negativity.
-
-  Below are the possible answers:
-
-  ## Very positive
-    It is certain.
-    It is decidedly so.
-    Without a doubt.
-    Yes - definitely.
-    You may rely on it.
-
-  ## Positive
-    As I see it, yes.
-    Most likely.
-    Outlook good.
-    Yes.
-    Signs point to yes.
-
-  ## Negative
-    Reply hazy, try again.
-    Ask again later.
-    Better not tell you now.
-    Cannot predict now.
-    Concentrate and ask again.
-
-  ## Very negative
-    Don't count on it.
-    My reply is no.
-    My sources say no.
-    Outlook not so good.
-    Very doubtful.
-*/
-
-// This should log "The ball has shaken!"
-// and return the answer.
+// Rahma _ Berhan 
+
+
+//declare 2D array to contain all messages each type in separated row 
+
+const arrayOfMessages = [
+    ["It is certain.",
+    "It is decidedly so.",
+    "Without a doubt.",
+    "Yes - definitely.",
+    "You may rely on it."] ,
+  
+    ["As I see it, yes.",
+    "Most likely.",
+    "Outlook good.",
+    "Yes.",
+    "Signs point to yes."] ,
+
+    ["Reply hazy, try again.",
+    "Ask again later.",
+    "Better not tell you now.",
+    "Cannot predict now.",
+    "Concentrate and ask again."] ,
+
+    ["Don't count on it.",
+    "My reply is no.",
+    "My sources say no.",
+    "Outlook not so good.",
+    "Very doubtful."] ];
+
+// declare random1 and random2 variables- and their values will be generated rondomly 
+// will use these two numbers to choose message from the array
+
+let random1;
+let random2;
+
+// this function will print message first, then will generate two numbers , then return message
 function shakeBall() {
-  //Write your code in here
+  console.log("The ball has shaken!");
+
+  random1 = Math.floor(Math.random() * arrayOfMessages.length);
+  random2 = Math.floor(Math.random() * arrayOfMessages.length);
+
+  return arrayOfMessages[random1][random2];
+  
 }
 
+
 /* 
   This function should say whether the answer it is given is
     - very positive
@@ -58,10 +55,53 @@ function shakeBall() {
 
   This function should expect to be called with any value which was returned by the shakeBall function.
 */
+
+// this function will check the array one by one to search for the message stored in answer
+// when the message is found ,it will save the row number in variable rowNum 
+// then it will move to switch to store the message type in type variable and then return it 
+
 function checkAnswer(answer) {
-  //Write your code in here
+  let type = "";
+  let rowNum = 0;
+  
+ //search for answer 
+  for (let i = 0 ; i <= 3 ; i++)
+  {
+    for (let j= 0 ;j<=4 ; j++)
+      {
+        if (answer == arrayOfMessages[i][j])
+          {
+            rowNum = i;
+          }
+      }
+  }
+
+//return message type depending on the rowNum 
+  switch (rowNum)
+  {
+    case 0:
+      type = "very positive";
+      break;
+
+    case 1:
+      type = "positive";
+      break;
+
+    case 2:
+      type = "negative";
+      break;
+
+    case 3:
+      type = "very negative";
+      break;
+  }
+  return type;
+
 }
 
+
+
+
 /* 
 ==================================
 ======= TESTS - DO NOT MODIFY =====
diff --git a/mandatory/1-syntax-errors.js b/mandatory/1-syntax-errors.js
index d9e004465..da559d4ec 100644
--- a/mandatory/1-syntax-errors.js
+++ b/mandatory/1-syntax-errors.js
@@ -1,16 +1,17 @@
 // 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 "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;
-
-  return "The total is total";
+  total = a + b;
+  return "The total is " + total;
 }
 
 /* 
diff --git a/mandatory/2-logic-error.js b/mandatory/2-logic-error.js
index 9eb8c8cd7..5152c982c 100644
--- a/mandatory/2-logic-error.js
+++ b/mandatory/2-logic-error.js
@@ -1,16 +1,16 @@
 // The syntax for these functions is valid but there are some errors, find them and fix them
 
 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..099c42c29 100644
--- a/mandatory/3-function-output.js
+++ b/mandatory/3-function-output.js
@@ -1,9 +1,11 @@
 // Add comments to explain what this function does. You're meant to use Google!
+//this function will generate a random number between 0 & 1 then multiply it by 10. 
 function getRandomNumber() {
   return Math.random() * 10;
 }
 
 // Add comments to explain what this function does. You're meant to use Google!
+//The concat() method joins two or more strings. So this function will join word1 & word2 in one sentence.
 function combine2Words(word1, word2) {
   return word1.concat(word2);
 }
@@ -11,6 +13,7 @@ function combine2Words(word1, 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, " ", thirdWord);
 }
 
 /* 
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index ba77c7ae2..2aa4e527d 100644
--- a/mandatory/4-tax.js
+++ b/mandatory/4-tax.js
@@ -4,8 +4,13 @@
   A business requires a program that calculates how much the price of a product is including sales tax
   Sales tax is 20% of the price of the product.
 */
+let price ;
+let total ;
 
-function calculateSalesTax() {}
+function calculateSalesTax(price) {
+  total = price + (0.20 * price); 
+  return total;
+}
 
 /*
   CURRENCY FORMATTING
@@ -17,7 +22,11 @@ function calculateSalesTax() {}
   Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
 */
 
-function addTaxAndFormatCurrency() {}
+function addTaxAndFormatCurrency(price) {
+  let tax = calculateSalesTax(price);
+  tax = parseFloat(tax).toFixed(2);
+  return `£${tax}`;
+}
 
 /* 
 ===================================================