diff --git a/extra/1-currency-conversion.js b/extra/1-currency-conversion.js
index 75b3c6aab..c17ca387b 100644
--- a/extra/1-currency-conversion.js
+++ b/extra/1-currency-conversion.js
@@ -5,17 +5,29 @@
   Write a function that converts a price to USD (exchange rate is 1.4 $ to £)
 */
 
-function convertToUSD() {}
+function convertToUSD(price1) {
+return price1 * 1.4;
+
+}
 
 /*
   CURRENCY CONVERSION
   ===================
   The business is now breaking into the Brazilian market
   Write a new function for converting to the Brazilian real (exchange rate is 5.7 BRL to £)
-  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.
+  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.
 */
+// let price=100;
+function convertToBRL(price) {
+ price=((price/100)*99)*5.7;
+ price=price.toFixed(2);
+  
+return parseFloat(price);
+
+}
+
 
-function convertToBRL() {}
 
 /* ======= 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..5fdaf4bf3 100644
--- a/extra/2-piping.js
+++ b/extra/2-piping.js
@@ -6,6 +6,7 @@
   - one that multiplies 2 numbers together
   - one that formats a number so it's returned as a string with a £ sign before it (e.g. 20 -> £20)
 
+
   2. Using the variable startingValue as input, perform the following operations using your functions all
   on one line (assign the result to the variable badCode):
   - add 10 to startingValue
@@ -16,26 +17,29 @@
   the final result to the variable goodCode
 */
 
-function add() {
-
+function add(a,b) {
+return a + b;
 }
 
-function multiply() {
-
+function multiply(a,b) {
+return a * b;
 }
 
-function format() {
-
+function format(numer) {
+return `£` + numer;
 }
-
+console.log(format(1));
 const startingValue = 2;
 
+
+
 // Why can this code be seen as bad practice? Comment your answer.
-let badCode =
+let badCode = format(multiply(add(startingValue, 10),2));
 
 /* BETTER PRACTICE */
-
-let goodCode =
+let result = add(startingValue,10);
+result=multiply(result,2);
+let goodCode = format(result);
 
 /* ======= 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/mandatory/1-syntax-errors.js b/mandatory/1-syntax-errors.js
index d9e004465..43cedda07 100644
--- a/mandatory/1-syntax-errors.js
+++ b/mandatory/1-syntax-errors.js
@@ -1,16 +1,16 @@
 // 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`;
-
+function introduceMe(name, age) {
+  return `Hello, my name is ${name} and I am ${age} years old`;
+}
 function getTotal(a, b) {
-  total = a ++ b;
+  total = a + b;
 
-  return "The total is total";
+  return `The total is ${total}`;
 }
 
 /* 
diff --git a/mandatory/2-logic-error.js b/mandatory/2-logic-error.js
index 9eb8c8cd7..ff5b064e1 100644
--- a/mandatory/2-logic-error.js
+++ b/mandatory/2-logic-error.js
@@ -1,16 +1,15 @@
 // 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..7c9471077 100644
--- a/mandatory/3-function-output.js
+++ b/mandatory/3-function-output.js
@@ -9,6 +9,7 @@ function combine2Words(word1, 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.
 }
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index ba77c7ae2..dfadb3870 100644
--- a/mandatory/4-tax.js
+++ b/mandatory/4-tax.js
@@ -5,7 +5,10 @@
   Sales tax is 20% of the price of the product.
 */
 
-function calculateSalesTax() {}
+function calculateSalesTax(price) {
+  const fullPrice = price + price / 5;
+  return fullPrice;
+}
 
 /*
   CURRENCY FORMATTING
@@ -17,8 +20,11 @@ function calculateSalesTax() {}
   Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
 */
 
-function addTaxAndFormatCurrency() {}
+function addTaxAndFormatCurrency(price) {
+  const prices = calculateSalesTax(price).toFixed(2);
 
+  return `£${prices}`;
+}
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====