diff --git a/exercises/C-variables/exercise.js b/exercises/C-variables/exercise.js
index a6bbb9786..6156b9a3d 100644
--- a/exercises/C-variables/exercise.js
+++ b/exercises/C-variables/exercise.js
@@ -1,3 +1,3 @@
 // Start by creating a variable `greeting`
-
+const greeting = "Hello"
 console.log(greeting);
diff --git a/exercises/D-strings/exercise.js b/exercises/D-strings/exercise.js
index 2cffa6a81..7d2497cfc 100644
--- a/exercises/D-strings/exercise.js
+++ b/exercises/D-strings/exercise.js
@@ -1,3 +1,4 @@
 // Start by creating a variable `message`
-
-console.log(message);
+var message = "CYF Rocks";
+var messageType = typeof message;
+console.log( messageType);
diff --git a/exercises/E-strings-concatenation/exercise.js b/exercises/E-strings-concatenation/exercise.js
index 2cffa6a81..38676e32d 100644
--- a/exercises/E-strings-concatenation/exercise.js
+++ b/exercises/E-strings-concatenation/exercise.js
@@ -1,3 +1,4 @@
 // Start by creating a variable `message`
-
-console.log(message);
+var greeting = "Hello";
+var myName = "Khaya";   
+console.log(greeting + " " + myName)
\ No newline at end of file
diff --git a/exercises/F-strings-methods/exercise.js b/exercises/F-strings-methods/exercise.js
index 2cffa6a81..638ddf34d 100644
--- a/exercises/F-strings-methods/exercise.js
+++ b/exercises/F-strings-methods/exercise.js
@@ -1,3 +1,4 @@
 // Start by creating a variable `message`
-
-console.log(message);
+var message = "Khaya";
+var messageLength = message.length;
+console.log(messageLength);
diff --git a/exercises/F-strings-methods/exercise2.js b/exercises/F-strings-methods/exercise2.js
index b4b46943d..87459c5ac 100644
--- a/exercises/F-strings-methods/exercise2.js
+++ b/exercises/F-strings-methods/exercise2.js
@@ -1,3 +1,3 @@
 const name = " Daniel  ";
-
-console.log(message);
+const message = name.length;
+console.log("My name is " + name.trim() + "and my name is " + message + " characters long" );
diff --git a/mandatory/1-syntax-errors.js b/mandatory/1-syntax-errors.js
index 0a21afd1b..dbd0453bf 100644
--- a/mandatory/1-syntax-errors.js
+++ b/mandatory/1-syntax-errors.js
@@ -1,17 +1,18 @@
 // 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 " + name "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;
+    total = a + b ;
 
-    return "The total is total"
+    return "The total is " + total;
 }
+*/
 
 /* 
 ===================================================
@@ -24,19 +25,22 @@ To run these tests type `node 1-syntax-errors.js` into your terminal
 ===================================================
 */
 
-const util = require('util');
+const until = require("until");
 
 function test(test_name, actual, expected) {
     let status;
     if (actual === expected) {
         status = "PASSED";
     } else {
-        status = `FAILED: expected: ${util.inspect(expected)} but your function returned: ${util.inspect(actual)}`;
+        status = `FAILED: expected: ${until.inspect(expected)
+        } 
+        but your function returned:${until.inspect(actual)}`;
     }
 
     console.log(`${test_name}: ${status}`);
 }
 
+
 test("fixed addNumbers function - case 1", addNumbers(3, 4, 6), 13);
 test("fixed introduceMe function", introduceMe("Sonjide", 27), "Hello, my name is Sonjide and I am 27 years old");
-test("fixed getTotal function", getTotal(23, 5), "The total is 28");
+test("fixed getTotal function", getTotal(23, 5), "The total is 28");
\ No newline at end of file
diff --git a/mandatory/2-logic-error.js b/mandatory/2-logic-error.js
index 3c578ad87..5c2022476 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 getWordLength(word) {
-  return "word".length();
+  return word.length();
 }
 
 function multiply(a, b, c) {
-  a * b * c;
-  return;
+  return a * b * c;
 }
 
 /* 
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index c9e41c691..212747d4f 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 amount = price * 0.2;
+  return amount;
+}
 
 /*
   CURRENCY FORMATTING
@@ -17,7 +20,10 @@ function calculateSalesTax() {}
   Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
 */
 
-function addTaxAndFormatCurrency() {}
+function addTaxAndFormatCurrency(total) {
+  const afterTax = calculateSalesTax(total).toFixed(2);
+  return `£${afterTax}`;
+}
 
 /* 
 ===================================================