diff --git a/Sprint-1/fix/median.js b/Sprint-1/fix/median.js
index b22590bc6..927259d82 100644
--- a/Sprint-1/fix/median.js
+++ b/Sprint-1/fix/median.js
@@ -6,9 +6,37 @@
 // or 'list' has mixed values (the function is expected to sort only numbers).
 
 function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+
+   // Check valid input -array
+  if(!Array.isArray(list) || list.length === 0) return null;
+  
+  // Filter non-numeric values
+
+  const numbers = list.filter(item => typeof item === 'number');
+  if (numbers.length === 0) return null;
+
+  // Sort the array
+
+  const sorted = [...numbers].sort((a, b) => a - b);
+
+   // Get the index of the middle item by rounding it using Math.floor()
+
+  const mid = Math.floor(sorted.length/2);  
+  
+  // for Odd number of items return the middle element
+
+  if (sorted.length % 2 !== 0) return sorted[mid];
+
+  // for even number of items 
+  return (sorted[mid - 1] + sorted[mid]) / 2;
+
 }
 
 module.exports = calculateMedian;
+
+
+// Implementation fixed 
+  
+  // const middleIndex = Math.floor(list.length / 2);
+  // const median = list.splice(middleIndex, 1)[0];
+  // return median;
diff --git a/Sprint-1/fix/median.test.js b/Sprint-1/fix/median.test.js
index 21da654d7..b637ac950 100644
--- a/Sprint-1/fix/median.test.js
+++ b/Sprint-1/fix/median.test.js
@@ -47,4 +47,4 @@ describe("calculateMedian", () => {
   ].forEach(({ input, expected }) =>
     it(`filters out non-numeric values and calculates the median for [${input}]`, () => expect(calculateMedian(input)).toEqual(expected))
   );
-});
+}); 
diff --git a/Sprint-1/implement/dedupe.js b/Sprint-1/implement/dedupe.js
index 781e8718a..949208ce5 100644
--- a/Sprint-1/implement/dedupe.js
+++ b/Sprint-1/implement/dedupe.js
@@ -1 +1,8 @@
-function dedupe() {}
+function dedupe(array) {
+  if (!Array.isArray(array)) throw new Error("Input must be an array");
+  return array.filter((item, index) => array.indexOf(item) === index);
+}
+console.log(dedupe(['a', 'a', 'a', 'b', 'b', 'c']));
+module.exports = dedupe;
+
+// Dedupe function implemented. 
\ No newline at end of file
diff --git a/Sprint-1/implement/dedupe.test.js b/Sprint-1/implement/dedupe.test.js
index 23e0f8638..87052d61a 100644
--- a/Sprint-1/implement/dedupe.test.js
+++ b/Sprint-1/implement/dedupe.test.js
@@ -16,12 +16,32 @@ E.g. dedupe([1, 2, 1]) target output: [1, 2]
 // Given an empty array
 // When passed to the dedupe function
 // Then it should return an empty array
-test.todo("given an empty array, it returns an empty array");
+
+test("given an empty array, it returns an empty array", () => {
+  expect(dedupe([])).toEqual([]);
+});
 
 // Given an array with no duplicates
 // When passed to the dedupe function
 // Then it should return a copy of the original array
 
+test("given an array with no duplicates returns a copy of the original array", () => {
+  expect(dedupe([1, 2, 3])).toEqual([1, 2, 3]);
+  expect(dedupe(['a', 'b', 'c'])).toEqual(['a', 'b', 'c']);
+});
+
 // Given an array with strings or numbers
 // When passed to the dedupe function
-// Then it should remove the duplicate values, preserving the first occurence of each element
+// Then it should remove the duplicate values, preserving the first occurrence of each element
+
+test("Given an array with duplicate strings removes duplicate strings", () => {
+  expect(dedupe(['a', 'a', 'a', 'b', 'b', 'c'])).toEqual(['a', 'b', 'c']);
+});
+
+// 
+
+test("Given an array removes duplicates but keeps first occurrence", () => {
+  expect(dedupe([1, 2, 1])).toEqual([1, 2]);
+});
+
+// Dedupe function implemented, test cases.. performed. 
\ No newline at end of file
diff --git a/Sprint-1/implement/max.js b/Sprint-1/implement/max.js
index 6dd76378e..7e29f6a15 100644
--- a/Sprint-1/implement/max.js
+++ b/Sprint-1/implement/max.js
@@ -1,4 +1,22 @@
-function findMax(elements) {
+function findMax(list) {
+
+    // check if input is array
+
+  if (!Array.isArray(list)) {
+    throw new Error("Input must be an array");
+  }
+
+  // filter out non-numeric values
+  list = list.filter((list) => typeof list === "number");
+
+  if (list.length === 0) {
+    return -Infinity;
+  }
+  if (list.length === 1) {
+    return list[0];
+  }
+
+  return Math.max(...list);
 }
 
 module.exports = findMax;
diff --git a/Sprint-1/implement/max.test.js b/Sprint-1/implement/max.test.js
index 82f18fd88..0cf9c58ea 100644
--- a/Sprint-1/implement/max.test.js
+++ b/Sprint-1/implement/max.test.js
@@ -16,28 +16,57 @@ const findMax = require("./max.js");
 // When passed to the max function
 // Then it should return -Infinity
 // Delete this test.todo and replace it with a test.
-test.todo("given an empty array, returns -Infinity");
+
+test("given an empty array, returns -Infinity", () => {
+  expect(findMax([])).toEqual(-Infinity);
+});
 
 // Given an array with one number
 // When passed to the max function
 // Then it should return that number
 
+test("given an array with one number, returns that number", () => {
+  expect(findMax([42])).toEqual(42);
+});
+
 // Given an array with both positive and negative numbers
 // When passed to the max function
 // Then it should return the largest number overall
 
+test("given an array with positive and negative numbers, returns the largest", () => {
+  expect(findMax([-10, 20, 5, -1])).toEqual(20);
+});
+
 // Given an array with just negative numbers
 // When passed to the max function
 // Then it should return the closest one to zero
 
+test("given an array with only negative numbers, returns the closest to zero", () => {
+  expect(findMax([-50, -10, -100])).toEqual(-10);
+});
+
 // Given an array with decimal numbers
 // When passed to the max function
 // Then it should return the largest decimal number
 
+test("given an array with decimal numbers, returns the largest decimal", () => {
+  expect(findMax([1.2, 3.5, 2.8])).toEqual(3.5);
+});
+
 // Given an array with non-number values
 // When passed to the max function
 // Then it should return the max and ignore non-numeric values
 
+test("given an array with non-number values, ignores them and returns the max number", () => {
+  expect(findMax(["a", 10, "b", 60, 10])).toEqual(60);
+});
+
 // Given an array with only non-number values
 // When passed to the max function
 // Then it should return the least surprising value given how it behaves for all other inputs
+
+test("given an array with only non-number values, returns -Infinity", () => {
+  expect(findMax(["a", "b", null, undefined])).toEqual(-Infinity);
+});
+
+// max.test.js test cases performed and function implemented
\ No newline at end of file
diff --git a/Sprint-1/implement/sum.js b/Sprint-1/implement/sum.js
index 9062aafe3..d2df411e5 100644
--- a/Sprint-1/implement/sum.js
+++ b/Sprint-1/implement/sum.js
@@ -1,4 +1,7 @@
 function sum(elements) {
+    return elements
+    .filter(elements => typeof elements === "number" && !Number.isNaN(elements))
+    .reduce((total, elements) => total + elements, 0);
 }
 
 module.exports = sum;
diff --git a/Sprint-1/implement/sum.test.js b/Sprint-1/implement/sum.test.js
index dd0a090ca..bc7ebe9bc 100644
--- a/Sprint-1/implement/sum.test.js
+++ b/Sprint-1/implement/sum.test.js
@@ -13,24 +13,47 @@ const sum = require("./sum.js");
 // Given an empty array
 // When passed to the sum function
 // Then it should return 0
-test.todo("given an empty array, returns 0")
+
+test("given an empty array, returns 0", () => {
+  expect(sum([])).toEqual(0);
+});
 
 // Given an array with just one number
 // When passed to the sum function
 // Then it should return that number
+test("given an array with one number, returns that number", () => {
+  expect(sum([5])).toEqual(5);
+});
 
 // Given an array containing negative numbers
 // When passed to the sum function
 // Then it should still return the correct total sum
 
+test("given an array with negative numbers, returns the correct sum", () => {
+  expect(sum([-5, 10, -5])).toEqual(0);
+});
+
 // Given an array with decimal/float numbers
 // When passed to the sum function
 // Then it should return the correct total sum
 
+test("given decimal numbers, returns the correct sum", () => {
+  expect(sum([1.5, 2.5])).toEqual(4);
+});
+
 // Given an array containing non-number values
 // When passed to the sum function
 // Then it should ignore the non-numerical values and return the sum of the numerical elements
 
+test("given non-number values, ignores them and returns sum of numeric values", () => {
+  expect(sum(["hey", 10, "hi", 60, 10])).toEqual(80);
+});
+
 // Given an array with only non-number values
 // When passed to the sum function
 // Then it should return the least surprising value given how it behaves for all other inputs
+test("given only non-number values, returns 0", () => {
+  expect(sum(["a", "b", null, undefined])).toEqual(0);
+});
+
+// Sum.test.js function implemented and tested. 
\ No newline at end of file
diff --git a/Sprint-1/refactor/includes.js b/Sprint-1/refactor/includes.js
index 29dad81f0..8c9ae2e66 100644
--- a/Sprint-1/refactor/includes.js
+++ b/Sprint-1/refactor/includes.js
@@ -1,8 +1,7 @@
 // Refactor the implementation of includes to use a for...of loop
 
 function includes(list, target) {
-  for (let index = 0; index < list.length; index++) {
-    const element = list[index];
+  for (const element of list) {
     if (element === target) {
       return true;
     }
diff --git a/Sprint-1/refactor/includes.test.js b/Sprint-1/refactor/includes.test.js
index 812158470..1a56dd7a3 100644
--- a/Sprint-1/refactor/includes.test.js
+++ b/Sprint-1/refactor/includes.test.js
@@ -36,3 +36,6 @@ test("searches for null", () => {
 
   expect(currentOutput).toEqual(targetOutput);
 });
+
+
+// include.test.js passed the test after refactoring the include-function with (for ... of)
\ No newline at end of file
diff --git a/Sprint-1/stretch/aoc-2018-day1/solution.js b/Sprint-1/stretch/aoc-2018-day1/solution.js
index e69de29bb..8c1cad305 100644
--- a/Sprint-1/stretch/aoc-2018-day1/solution.js
+++ b/Sprint-1/stretch/aoc-2018-day1/solution.js
@@ -0,0 +1,28 @@
+// We need to import file system and path for our task 
+
+const fs = require("fs");
+const path = require("path");
+
+function solution() {
+
+  // set file path
+
+  const inputFilePath = path.join(__dirname, "input.txt");
+
+  // read the file content
+  let fileContent = fs.readFileSync(inputFilePath, "utf-8");
+
+  // split the content into lines and convert each line to a number
+  let numbersArray = fileContent.split("\n").map(num => Number(num));
+
+  // calculate the sum of all numbers
+  const sumOfNumbers = numbersArray.reduce((sum, num) => sum + num, 0);
+
+  return sumOfNumbers;
+}
+
+console.log(solution());
+
+module.exports = solution;
+
+// A solution to add-up frequency values in input.txt
\ No newline at end of file