diff --git a/exercises/B-hello-world/exercise.js b/exercises/B-hello-world/exercise.js
index b179ee953..5a5e1a685 100644
--- a/exercises/B-hello-world/exercise.js
+++ b/exercises/B-hello-world/exercise.js
@@ -1 +1,3 @@
-console.log("Hello world");
+console.log(78967868678);
+
+console.log("Hello World.I just started learning JavaScript!");
\ No newline at end of file
diff --git a/exercises/C-variables/exercise.js b/exercises/C-variables/exercise.js
index a6bbb9786..68c55c70d 100644
--- a/exercises/C-variables/exercise.js
+++ b/exercises/C-variables/exercise.js
@@ -1,3 +1,7 @@
 // Start by creating a variable `greeting`
-
+var greeting = "Hello world";
+console.log(greeting);
+console.log(greeting);
+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..c950961db 100644
--- a/exercises/D-strings/exercise.js
+++ b/exercises/D-strings/exercise.js
@@ -1,3 +1,5 @@
 // Start by creating a variable `message`
-
+var message = "This is a string";
+var messageType = typeof message;   
 console.log(message);
+console.log(messageType);
diff --git a/exercises/E-strings-concatenation/exercise.js b/exercises/E-strings-concatenation/exercise.js
index 2cffa6a81..98c461e0d 100644
--- a/exercises/E-strings-concatenation/exercise.js
+++ b/exercises/E-strings-concatenation/exercise.js
@@ -1,3 +1,7 @@
 // Start by creating a variable `message`
+var greetingStart = "Hello, my name is ";
+var name1 = "Oleks. ";
+var you = "And you ? "
+var greeting = greetingStart + name1 + you;
 
-console.log(message);
+console.log(greeting);
diff --git a/exercises/F-strings-methods/exercise.js b/exercises/F-strings-methods/exercise.js
index 2cffa6a81..1c016a4f2 100644
--- a/exercises/F-strings-methods/exercise.js
+++ b/exercises/F-strings-methods/exercise.js
@@ -1,3 +1,25 @@
 // Start by creating a variable `message`
-
+var name1 = "Oleks";
+var nameLength = name1.length;
+var introduce1 = " My name is Oleks and my name is ";
+var introduce2 = "characters long.";
+var message = introduce1 + nameLength + " " + introduce2;
 console.log(message);
+// second way
+var name1 = "Oleks";
+var nameLength = name1.length;
+var introduce1 = "      My name is ";
+var introduce3 = "and my name is ";
+var introduce2 = "characters long.";
+var message = introduce1 + name1 + " "+ introduce3 + 
+nameLength + " " + introduce2;
+console.log(message);
+// trim method
+var name1 = "Oleks";
+var nameLength = name1.length;
+var introduce1 = " My name is ";
+var introduce3 = "and my name is ";
+var introduce2 = "characters long.";
+var message =
+  introduce1 + name1 + " " + introduce3 + nameLength + " " + introduce2;
+console.log(message.trim());
\ No newline at end of file
diff --git a/exercises/F-strings-methods/exercise2.js b/exercises/F-strings-methods/exercise2.js
index b4b46943d..d1edb205f 100644
--- a/exercises/F-strings-methods/exercise2.js
+++ b/exercises/F-strings-methods/exercise2.js
@@ -1,3 +1,20 @@
 const name = " Daniel  ";
 
+var name1 = "Oleks";
+var nameLength = name1.length;
+var introduce1 = "      My name is ";
+var introduce3 = "and my name is ";
+var introduce2 = "characters long.";
+var message =
+  introduce1 + name1 + " " + introduce3 + nameLength + " " + introduce2;
 console.log(message);
+// trim method
+var name1 = "Oleks";
+var nameLength = name1.length;
+var introduce1 = " My name is ";
+var introduce3 = "and my name is ";
+var introduce2 = "characters long.";
+var message =
+  introduce1 + name1 + " " + introduce3 + nameLength + " " + introduce2;
+console.log(message.trim());
+
diff --git a/exercises/G-numbers/exercise.js b/exercises/G-numbers/exercise.js
index 49e7bc00b..64f40203b 100644
--- a/exercises/G-numbers/exercise.js
+++ b/exercises/G-numbers/exercise.js
@@ -1 +1,12 @@
 // Start by creating a variables `numberOfStudents` and `numberOfMentors`
+var numberOfStudents = 50;
+var numberOfMentors = 10;
+var stud = "Number of students: ";
+console.log(stud + numberOfStudents);
+var ment = "Number of mentors: ";
+console.log(ment + numberOfMentors);
+var total = "Total number of students and mentors: ";
+var sum = numberOfMentors + numberOfStudents;
+console.log(total + sum);
+
+
diff --git a/exercises/I-floats/exercise.js b/exercises/I-floats/exercise.js
index a5bbcd852..0e2580730 100644
--- a/exercises/I-floats/exercise.js
+++ b/exercises/I-floats/exercise.js
@@ -1,2 +1,29 @@
 var numberOfStudents = 15;
 var numberOfMentors = 8;
+var preciseAge = 30.612437;
+varroughAge = Math.round(preciseAge); // 30
+console.log(varroughAge);
+
+//from G ex + new solution
+
+var stud = "Number of students: ";
+console.log(stud + numberOfStudents);
+var ment = "Number of mentors: ";
+console.log(ment + numberOfMentors);
+var total = "Total number of students and mentors: ";
+var sum = numberOfMentors + numberOfStudents;
+console.log(total + sum);
+var percentageStudents = 100*numberOfStudents/sum
+var percentageMentors = 100*numberOfMentors/sum
+var roundStudents = Math.round(percentageStudents);
+var roundMentors = Math.round(percentageMentors);
+
+console.log("Percentage mentors: " + roundMentors + " %.");
+console.log("Percentage students: " + roundStudents + " %.");
+//     Result 
+//     31
+//    Number of students: 15
+//    Number of mentors: 8
+//    Total number of students and mentors: 23
+//    Percentage mentors: 35 %.
+//    Percentage students: 65 %.
\ No newline at end of file
diff --git a/exercises/J-functions/exercise.js b/exercises/J-functions/exercise.js
index 0ae5850e5..4aa15efc3 100644
--- a/exercises/J-functions/exercise.js
+++ b/exercises/J-functions/exercise.js
@@ -1,7 +1,21 @@
 function halve(number) {
-  // complete the function here
+ return number/2;
 }
 
 var result = halve(12);
+console.log("result 12/2=", result);
 
-console.log(result);
+var result = halve(24);
+console.log("result 24/2=", result);
+
+var result = halve(100);
+console.log("result 100/2=", result);
+
+var result = halve(365);
+
+console.log("result 365/2=", result);
+
+//  result 12/2= 6
+//  result 24/2= 12
+//  result 100/2= 50
+//  result 365/2= 182.5
\ No newline at end of file
diff --git a/exercises/J-functions/exercise2.js b/exercises/J-functions/exercise2.js
index 82ef5e780..453519c6f 100644
--- a/exercises/J-functions/exercise2.js
+++ b/exercises/J-functions/exercise2.js
@@ -1,7 +1,9 @@
 function triple(number) {
-  // complete function here
+ return number*3;
 }
 
 var result = triple(12);
 
-console.log(result);
+console.log("result 12 x 3 = ", result);
+
+//   result 12 x 3 =  36
diff --git a/exercises/K-functions-parameters/README.md b/exercises/K-functions-parameters/README.md
index 1614e221b..c850a7526 100644
--- a/exercises/K-functions-parameters/README.md
+++ b/exercises/K-functions-parameters/README.md
@@ -1,4 +1,4 @@
-The input given to a function is called a **parameter**.
+"The input given to a function is called a **parameter**.
 
 A function can take more than one parameter:
 
diff --git a/exercises/K-functions-parameters/exercise.js b/exercises/K-functions-parameters/exercise.js
index 8d5db5e69..9fa5abf89 100644
--- a/exercises/K-functions-parameters/exercise.js
+++ b/exercises/K-functions-parameters/exercise.js
@@ -1,9 +1,9 @@
 // Complete the function so that it takes input parameters
-function multiply() {
-  // Calculate the result of the function and return it
+function multiply(a, b) {
+  return a * b;
 }
 
 // Assign the result of calling the function the variable `result`
 var result = multiply(3, 4);
 
-console.log(result);
+console.log("result 3*4 = ", result);
diff --git a/exercises/K-functions-parameters/exercise2.js b/exercises/K-functions-parameters/exercise2.js
index db7a8904b..d2bb1d2cd 100644
--- a/exercises/K-functions-parameters/exercise2.js
+++ b/exercises/K-functions-parameters/exercise2.js
@@ -1,5 +1,7 @@
 // Declare your function first
-
+function divide ( a, b) {
+    return a / b;
+}
 var result = divide(3, 4);
 
-console.log(result);
+console.log("a / b = ", result);
diff --git a/exercises/K-functions-parameters/exercise3.js b/exercises/K-functions-parameters/exercise3.js
index 537e9f4ec..81f47c3b0 100644
--- a/exercises/K-functions-parameters/exercise3.js
+++ b/exercises/K-functions-parameters/exercise3.js
@@ -1,5 +1,8 @@
-// Write your function here
-
+function createGreeting(name) {
+    return ("Hello, my name is " + name );
+}
 var greeting = createGreeting("Daniel");
 
 console.log(greeting);
+
+//  Hello, my name is Daniel
\ No newline at end of file
diff --git a/exercises/K-functions-parameters/exercise4.js b/exercises/K-functions-parameters/exercise4.js
index 7ab44589e..b4ee9c0cc 100644
--- a/exercises/K-functions-parameters/exercise4.js
+++ b/exercises/K-functions-parameters/exercise4.js
@@ -1,5 +1,7 @@
 // Declare your function first
-
+function summ(a, b) {
+    return a + b 
+}
 // Call the function and assign to a variable `sum`
-
-console.log(sum);
+var sum = summ(13, 124);
+console.log("13 + 124 = ", sum);
diff --git a/exercises/K-functions-parameters/exercise5.js b/exercises/K-functions-parameters/exercise5.js
index 7c5bcd605..938319e2d 100644
--- a/exercises/K-functions-parameters/exercise5.js
+++ b/exercises/K-functions-parameters/exercise5.js
@@ -1,5 +1,11 @@
 // Declare your function here
-
+function createLongGreeting(name, age) {
+    return ("Hello, my name is " + name + " and I am "
+     + age + " years old")
+}
 const greeting = createLongGreeting("Daniel", 30);
 
 console.log(greeting);
+
+
+//      Hello, my name is Daniel and I am 30 years old
\ No newline at end of file
diff --git a/exercises/L-functions-nested/exercise.js b/exercises/L-functions-nested/exercise.js
index a5d377442..f78ed6f18 100644
--- a/exercises/L-functions-nested/exercise.js
+++ b/exercises/L-functions-nested/exercise.js
@@ -3,3 +3,19 @@ var mentor2 = "Irina";
 var mentor3 = "Mimi";
 var mentor4 = "Rob";
 var mentor5 = "Yohannes";
+
+function shoutyGreeting(mentor) {
+    return ("HELLO," + " " + mentor.toUpperCase() + " !")
+}
+console.log(shoutyGreeting(mentor1));
+console.log(shoutyGreeting(mentor2));
+console.log(shoutyGreeting(mentor3));
+console.log(shoutyGreeting(mentor4));
+console.log(shoutyGreeting(mentor5));
+
+//    Result a shouty greeting to each one mentors:  
+//     HELLO, DANIEL !
+//     HELLO, IRINA !
+//     HELLO, MIMI !
+//     HELLO, ROB !
+//     HELLO, YOHANNES !
\ No newline at end of file
diff --git a/extra/1-currency-conversion.js b/extra/1-currency-conversion.js
index 75b3c6aab..f58d96a6c 100644
--- a/extra/1-currency-conversion.js
+++ b/extra/1-currency-conversion.js
@@ -5,7 +5,11 @@
   Write a function that converts a price to USD (exchange rate is 1.4 $ to £)
 */
 
-function convertToUSD() {}
+function convertToUSD(price) {
+  let dol = (price*1.4).toFixed(2);
+  return Number(dol);
+}
+
 
 /*
   CURRENCY CONVERSION
@@ -15,7 +19,9 @@ 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(price) {
+  return Number((price*0.99*5.7).toFixed(2));
+}
 
 /* ======= 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..1bbe727e4 100644
--- a/extra/2-piping.js
+++ b/extra/2-piping.js
@@ -16,26 +16,29 @@
   the final result to the variable goodCode
 */
 
-function add() {
-
+function add(number1, number2) {
+return number1 + number2;
 }
 
-function multiply() {
-
+function multiply(number1, number2) {
+return number1 * number2;
 }
 
-function format() {
-
+function format(n) {
+return "£" + n;
 }
 
 const startingValue = 2;
 
 // Why can this code be seen as bad practice? Comment your answer.
-let badCode =
+let badCode = format(multiply(add(startingValue, 10), startingValue)); // Because vjhjjk
 
 /* BETTER PRACTICE */
 
-let goodCode =
+let sum = add(startingValue, 10);
+let multiplies = multiply(sum, startingValue);
+let formNumber = format(multiplies);
+let goodCode = formNumber;
 
 /* ======= 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..f93875960 100644
--- a/extra/3-magic-8-ball.js
+++ b/extra/3-magic-8-ball.js
@@ -43,10 +43,59 @@
     Very doubtful.
 */
 
+// This should log "The ball has shaken!"
+// and return the answer.------------------------------------------------------------------HERE
+//function shakeBall() {
+  //Write your code in here
+//}
+
+
+
+let veryPositiveAnswers = [
+  "It is certain.",
+  "It is decidedly so.",
+  "Without a doubt.",
+  "Yes - definitely.",
+  "You may rely on it.",
+];
+
+let positiveAnswers = [
+  "As I see it, yes.",
+  "Most likely.",
+  "Outlook good.",
+  "Yes.",
+  "Signs point to yes.",
+];
+
+let negativeAnswers = [
+  "Reply hazy, try again.",
+  "Ask again later.",
+  "Better not tell you now.",
+  "Cannot predict now.",
+  "Concentrate and ask again.",
+];
+
+let veryNegativeAnswers = [
+  "Don't count on it.",
+  "My reply is no.",
+  "My sources say no.",
+  "Outlook not so good.",
+  "Very doubtful.",
+];
+
+let allAnswers = [
+  ...veryPositiveAnswers,
+  ...positiveAnswers,
+  ...negativeAnswers,
+  ...veryNegativeAnswers,
+];
+
 // This should log "The ball has shaken!"
 // and return the answer.
 function shakeBall() {
-  //Write your code in here
+  console.log("The ball has shaken!");
+  let randomIndex = Math.floor(Math.random() * allAnswers.length);
+  return allAnswers[randomIndex];
 }
 
 /* 
@@ -59,9 +108,39 @@ function shakeBall() {
   This function should expect to be called with any value which was returned by the shakeBall function.
 */
 function checkAnswer(answer) {
-  //Write your code in here
+  if (veryPositiveAnswers.includes(answer)) {
+    return "very positive";
+  } else if (positiveAnswers.includes(answer)) {
+    return "positive";
+  } else if (negativeAnswers.includes(answer)) {
+    return "negative";
+  } else if (veryNegativeAnswers.includes(answer)) {
+    return "very negative";
+  }
 }
 
+const foo = shakeBall();
+const bar = checkAnswer(foo);
+console.log(bar);
+
+
+
+
+
+
+/* 
+  This function should say whether the answer it is given is
+    - very positive
+    - positive
+    - negative
+    - very negative
+
+  This function should expect to be called with any value which was returned by the shakeBall function.----------------------------HERE
+*/
+   //function checkAnswer(answer) {
+  //Write your code in here
+   //}
+
 /* 
 ==================================
 ======= TESTS - DO NOT MODIFY =====
diff --git a/mandatory/1-syntax-errors.js b/mandatory/1-syntax-errors.js
index a10cc9ac2..89ceb13f0 100644
--- a/mandatory/1-syntax-errors.js
+++ b/mandatory/1-syntax-errors.js
@@ -1,18 +1,15 @@
 // There are syntax errors in this code - can you fix it to pass the tests?
 
-function addNumbers(a b c) {
-  return 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";
+  const total = a + b;
+  return 'The total is ' + total;
 }
-
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====
diff --git a/mandatory/2-logic-error.js b/mandatory/2-logic-error.js
index 9cca7603b..995910d8d 100644
--- a/mandatory/2-logic-error.js
+++ b/mandatory/2-logic-error.js
@@ -1,16 +1,15 @@
 // 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..e2425c6f4 100644
--- a/mandatory/3-function-output.js
+++ b/mandatory/3-function-output.js
@@ -1,18 +1,30 @@
 // Add comments to explain what this function does. You're meant to use Google!
+//  The Math.random() function returns a floating-point, pseudo-random number 
+//that's greater than or equal to 0 and less than 1, with approximately uniform 
+//distribution over that range — which you can then scale to your desired range. 
+//The implementation selects the initial seed to the random number generation 
+//algorithm; it cannot be chosen or reset by the user.
+//Return value A floating-point, pseudo-random number between 0 (inclusive) and 1 (exclusive).
+//  0 < Number <  10 ;
+
 function getRandomNumber() {
   return Math.random() * 10;
 }
 
 // Add comments to explain what this function does. You're meant to use Google!
+// The concat function concatenates two or more strings and returns the resulting string.
+//Syntax :   concat( string1, string2 [,string]* )
+//
 function combine2Words(word1, word2) {
   return word1.concat(word2);
 }
 
 function concatenate(firstWord, secondWord, thirdWord) {
+  return firstWord.concat(" ", 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.
 }
-
+console.log(concatenate("code", "your", "future"));
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index ba77c7ae2..491edbe72 100644
--- a/mandatory/4-tax.js
+++ b/mandatory/4-tax.js
@@ -5,8 +5,10 @@
   Sales tax is 20% of the price of the product.
 */
 
-function calculateSalesTax() {}
-
+function calculateSalesTax(price) {
+let tax = price*0.2;
+return price + tax;
+}
 /*
   CURRENCY FORMATTING
   ===================
@@ -17,7 +19,10 @@ 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 newPrice = calculateSalesTax(price);
+  return "£" + newPrice.toFixed(2);
+}
 
 /* 
 ===================================================
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"
+        ]
       }
     ]
   },