diff --git a/js1-week1.js b/js1-week1.js
new file mode 100644
index 000000000..9711d5539
--- /dev/null
+++ b/js1-week1.js
@@ -0,0 +1,20 @@
+console.log("Hello World")
+let greeting = "Helen";
+console.log(greeting)
+console.log(greeting)
+console.log(greeting)
+let colors = "blue,yellow";
+typeof(colors)
+typeof(2)
+let dear="How are you doing ";
+let myName="Melese";
+let Greeting= dear + myName;
+let numberOfTraineers = 30;
+let numberOfMentors = 40;
+let total_number_of_trainees = numberOfTraineers + numberOfMentors;
+console.log(total_number_of_trainees)
+
+let numberofTraineersinpercent = Math.round((numberOfTraineers/total_number_of_trainees)*100) + "%";
+let numberofMentorsinpercent = Math.round(( numberOfMentors/total_number_of_trainees)*100) + "%";
+console.log(numberofTraineersinpercent)
+console.log(numberofMentorsinpercent)
\ No newline at end of file
diff --git a/mandatory/1-syntax-errors.js b/mandatory/1-syntax-errors.js
index d9e004465..abd5b0339 100644
--- a/mandatory/1-syntax-errors.js
+++ b/mandatory/1-syntax-errors.js
@@ -1,17 +1,21 @@
 // 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 "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);
 }
+addNumbers(3,4,6);
+introduceMe('Sonjide',27);
+getTotal(23,5);
+
 
 /* 
 ===================================================
diff --git a/mandatory/2-logic-error.js b/mandatory/2-logic-error.js
index 9eb8c8cd7..147c0d1ac 100644
--- a/mandatory/2-logic-error.js
+++ b/mandatory/2-logic-error.js
@@ -1,18 +1,23 @@
 // 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);
+  
 }
-
+trimWord("   CodeYourFuture ");
+trimWord(" CodeYourFuture teaches coding     ");
+getStringLength("Turtles");
+getStringLength("A wild sentence appeared!");
+multiply(2, 3, 6);
+multiply(2, 3, 4);
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====
diff --git a/mandatory/3-function-output.js b/mandatory/3-function-output.js
index 5a953ba60..3324591d1 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 getRandomNumber function let you to get a random number greater than 0 and less than 10.
 function getRandomNumber() {
   return Math.random() * 10;
 }
 
 // Add comments to explain what this function does. You're meant to use Google!
+// The concat function merge two strings into one.
 function combine2Words(word1, word2) {
   return word1.concat(word2);
 }
@@ -11,8 +13,11 @@ 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);
 }
-
+concatenate("code ", "your ", "future");
+concatenate("I ", "like ", "pizza");
+concatenate("I ", "am ", 13);
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====
diff --git a/mandatory/4-tax.js b/mandatory/4-tax.js
index ba77c7ae2..1535eda30 100644
--- a/mandatory/4-tax.js
+++ b/mandatory/4-tax.js
@@ -5,7 +5,9 @@
   Sales tax is 20% of the price of the product.
 */
 
-function calculateSalesTax() {}
+function calculateSalesTax(product) {
+  return (product + (product*20)/100)
+}
 
 /*
   CURRENCY FORMATTING
@@ -17,7 +19,16 @@ function calculateSalesTax() {}
   Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
 */
 
-function addTaxAndFormatCurrency() {}
+function addTaxAndFormatCurrency(product) {
+  return "£"+(Math.round(calculateSalesTax(product)).toFixed(2))
+         
+}
+calculateSalesTax(15);
+calculateSalesTax(17.5);
+calculateSalesTax(34);
+addTaxAndFormatCurrency(15);
+addTaxAndFormatCurrency(17.5);
+addTaxAndFormatCurrency(34);
 
 /* 
 ===================================================