diff --git a/Sprint-1/fix/median.js b/Sprint-1/fix/median.js
index b22590bc6..2eaa988b0 100644
--- a/Sprint-1/fix/median.js
+++ b/Sprint-1/fix/median.js
@@ -6,9 +6,25 @@
 // or 'list' has mixed values (the function is expected to sort only numbers).
 
 function calculateMedian(list) {
+  if (!Array.isArray(list)) {
+    return null;
+  }
+
+  list = list.filter((value) => Number.isFinite(value));
+
+  if (list.length === 0) {
+    return null;
+  }
+
+  list.sort((a, b) => a - b);
+
   const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+
+  if (list.length % 2 === 0) {
+    return (list[middleIndex - 1] + list[middleIndex]) / 2;
+  } else {
+    return list[middleIndex];
+  }
 }
 
 module.exports = calculateMedian;
diff --git a/Sprint-1/implement/dedupe.js b/Sprint-1/implement/dedupe.js
index 781e8718a..6d179de93 100644
--- a/Sprint-1/implement/dedupe.js
+++ b/Sprint-1/implement/dedupe.js
@@ -1 +1,13 @@
-function dedupe() {}
+function dedupe(arr) {
+  if (arr.length === 0) {
+    return [];
+  }
+  const uniqueSet = new Set(arr);
+  if (arr.length !== uniqueSet.size) {
+    return [...uniqueSet];
+  } else {
+    return [...arr];
+  }
+}
+
+module.exports = dedupe;
diff --git a/Sprint-1/implement/dedupe.test.js b/Sprint-1/implement/dedupe.test.js
index 23e0f8638..a2cb24bc9 100644
--- a/Sprint-1/implement/dedupe.test.js
+++ b/Sprint-1/implement/dedupe.test.js
@@ -16,12 +16,40 @@ 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("The function should return a copy of the original array if the array contains no duplicates", () => {
+  const original1 = [2, 4, 5, 6, 8];
+  expect(original1.length).toBe(new Set(original1).size);
+  const result1 = dedupe(original1);
+  expect(result1).toEqual([2, 4, 5, 6, 8]);
+  expect(result1).not.toBe(original1);
 
+  const original2 = [3, 9, 25, 1, 12, 42];
+  expect(original2.length).toBe(new Set(original2).size);
+  const result2 = dedupe(original2);
+  expect(result2).toEqual([3, 9, 25, 1, 12, 42]);
+  expect(result2).not.toBe(original2);
+});
 // 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
+test("The function should return a clean array when a duplicated array is passed", () => {
+  expect(dedupe([2, 2, 4, 4, 5, 5, 6, 6, 6, 6, 8, 8, 8, 8])).toEqual([
+    2, 4, 5, 6, 8,
+  ]);
+  expect(dedupe([1, 1, 1, 2, 2, 3, 3, 4, 4, 6, 6, 7, 7, 8])).toEqual([
+    1, 2, 3, 4, 6, 7, 8,
+  ]);
+  expect(
+    dedupe(["ahmed", "ahmed", "chris", "chris", "tom", "tom", "joy"])
+  ).toEqual(["ahmed", "chris", "tom", "joy"]);
+  expect(
+    dedupe([2, 2, "apple", "apple", 5, 5, "samsung", "samsung", 8, 8])
+  ).toEqual([2, "apple", 5, "samsung", 8]);
+});
diff --git a/Sprint-1/implement/max.js b/Sprint-1/implement/max.js
index 6dd76378e..13969986b 100644
--- a/Sprint-1/implement/max.js
+++ b/Sprint-1/implement/max.js
@@ -1,4 +1,20 @@
 function findMax(elements) {
+  if (elements.length === 0) {
+    return -Infinity;
+  }
+
+  const number = elements.filter((value) => typeof value === "number");
+
+  if (number.length === 0) {
+    return undefined;
+  }
+  let maxNumber = number[0];
+  for (let i = 1; i < number.length; i++) {
+    if (number[i] > maxNumber) {
+      maxNumber = number[i];
+    }
+  }
+  return maxNumber;
 }
 
 module.exports = findMax;
diff --git a/Sprint-1/implement/max.test.js b/Sprint-1/implement/max.test.js
index 82f18fd88..ef546eb1d 100644
--- a/Sprint-1/implement/max.test.js
+++ b/Sprint-1/implement/max.test.js
@@ -16,28 +16,59 @@ 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("the function should return -Infinity when an empty array is passed to the function", () => {
+  expect(findMax([])).toEqual(-Infinity);
+});
 
 // Given an array with one number
 // When passed to the max function
 // Then it should return that number
-
+test("The function should return the original value when an array with one number is passed", () => {
+  expect(findMax([17])).toBe(17);
+  expect(findMax([8])).toBe(8);
+  expect(findMax([4])).toBe(4);
+});
 // Given an array with both positive and negative numbers
 // When passed to the max function
 // Then it should return the largest number overall
-
+test("The function should return the max value when an Integers number array is passed", () => {
+  expect(findMax([-3, -1, 0, 1, 3, 4, 6, 7])).toBe(7);
+  expect(findMax([-17, -8, -5, 2, 3, 0, 1])).toBe(3);
+  expect(findMax([-27, 18, -16, -9, 1, 7, 9])).toBe(18);
+});
 // Given an array with just negative numbers
 // When passed to the max function
 // Then it should return the closest one to zero
+test("The function should return the closest one to zero when an negative number array is passed", () => {
+  expect(findMax([-3, -1, -4, -6, -7])).toBe(-1);
+  expect(findMax([-17, -8, -5, -2, -3])).toBe(-2);
+  expect(findMax([-27, -18, -32, -67, -78, -70])).toBe(-18);
+});
 
 // Given an array with decimal numbers
 // When passed to the max function
 // Then it should return the largest decimal number
+test("The function should return the closest one to zero when an negative number array is passed", () => {
+  expect(findMax([3.5, 1.9, 5.4, 0.6, 3.7])).toBe(5.4);
+  expect(findMax([1.7, 0.8, 2.532, 1.092, 0.3])).toBe(2.532);
+  expect(findMax([0.27, 0.18, 0.32, 0.67, 0.78, 0.7])).toBe(0.78);
+});
 
 // 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("The function should return the closest one to zero when an negative number array is passed", () => {
+  expect(findMax([3.5, "Leeds", "300", "London", 3.7])).toBe(3.7);
+  expect(findMax(["1.778", "italy", 0.8, 0.88, 0.89, "base"])).toBe(0.89);
+  expect(findMax([0.27, "jerry", "140", 0.32, "apple", 0.78, "fly"])).toBe(
+    0.78
+  );
+});
 
 // 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("the function should return undefined when non-number value is passed", () => {
+  expect(findMax(["Manchester", "4000", "Leeds", "London"])).toBe(undefined);
+  expect(findMax(["orange", "apple", "5", "banana"])).toBe(undefined);
+});
diff --git a/Sprint-1/implement/sum.js b/Sprint-1/implement/sum.js
index 9062aafe3..8d7b51d52 100644
--- a/Sprint-1/implement/sum.js
+++ b/Sprint-1/implement/sum.js
@@ -1,4 +1,17 @@
 function sum(elements) {
+  if (elements.length === 0) {
+    return 0;
+  }
+  const number = elements.filter((value) => typeof value === "number");
+  if (number.length === 0) {
+    return undefined;
+  }
+  let sum = 0;
+  for (let i = 0; i < number.length; i++) {
+    sum += number[i];
+  }
+
+  return sum;
 }
 
 module.exports = sum;
diff --git a/Sprint-1/implement/sum.test.js b/Sprint-1/implement/sum.test.js
index dd0a090ca..c2e9e8ee8 100644
--- a/Sprint-1/implement/sum.test.js
+++ b/Sprint-1/implement/sum.test.js
@@ -13,24 +13,55 @@ 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("The function should return 0 when an empty array is passed", () => {
+  expect(sum([])).toEqual(0);
+});
 
 // Given an array with just one number
 // When passed to the sum function
 // Then it should return that number
-
+test("The function should return single value when single value array is passed", () => {
+  expect(sum([7])).toEqual(7);
+  expect(sum([14])).toEqual(14);
+  expect(sum([0])).toEqual(0);
+  expect(sum([100])).toEqual(100);
+});
 // Given an array containing negative numbers
 // When passed to the sum function
 // Then it should still return the correct total sum
-
+test("The function should return the correct total value when negative number array is passed", () => {
+  expect(sum([-7, -10, -33])).toEqual(-50);
+  expect(sum([-6, -10, -18, -4])).toEqual(-38);
+  expect(sum([-100, -10, -1, -20])).toEqual(-131);
+  expect(sum([-12, -23, -34, -45, -56, -67])).toEqual(-237);
+});
 // Given an array with decimal/float numbers
 // When passed to the sum function
 // Then it should return the correct total sum
-
+test("The function should return the correct total value when decimal/float numbers array is passed", () => {
+  expect(sum([7.8045, 1.273, 3.19])).toBeCloseTo(12.2675, 4);
+  expect(sum([4.6, 1.8, 3.18, 5.4])).toBeCloseTo(14.98);
+  expect(sum([11 / 12, 4 / 6, 1 / 2, 6 / 20])).toBeCloseTo(2.383333, 6);
+  expect(sum([1 / 2, 2 / 3, 3 / 4, 4 / 5, 5 / 6, 6 / 7])).toBeCloseTo(
+    4.407142857,
+    9
+  );
+});
 // 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("The function should return the correct total value when an array containing non-number values is passed", () => {
+  expect(sum([7.8045, "two", 3.19])).toEqual(10.9945);
+  expect(sum(["one", 1.8, 3.18, "zero"])).toEqual(4.98);
+  expect(sum([1 / 12, 4 / 6, "Ahmed", 6 / 8])).toEqual(1.5);
+  expect(sum(["one", "two", "three", "four", "five", 1 / 2])).toEqual(0.5);
+});
 // 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("The function should return undefined when an array with only non-number values is passed", () => {
+  expect(sum(["male", "two", "age"])).toEqual(undefined);
+  expect(sum(["one", "zero"])).toEqual(undefined);
+  expect(sum(["world", "apple", "Ahmed", "london"])).toEqual(undefined);
+  expect(sum(["one", "two", "three", "four", "five"])).toEqual(undefined);
+});
diff --git a/Sprint-1/refactor/includes.js b/Sprint-1/refactor/includes.js
index 29dad81f0..994131c59 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 (let element of list) {
     if (element === target) {
       return true;
     }