diff --git a/Sprint-1/fix/median.js b/Sprint-1/fix/median.js
index b22590bc6..7efb691f9 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) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+  if (!Array.isArray(list)) {
+    return null;
+  }
+
+  const numbers = list.filter(item => typeof item === "number");
+
+  if (numbers.length === 0) {
+    return null;
+  }
+
+  numbers.sort((a, b) => a - b);
+
+  const middleIndex = Math.floor(numbers.length / 2);
+
+  if (numbers.length % 2 !== 0) {
+    return numbers[middleIndex];
+  }
+
+  return (numbers[middleIndex - 1] + numbers[middleIndex]) / 2;
 }
 
 module.exports = calculateMedian;
diff --git a/Sprint-1/implement/dedupe.js b/Sprint-1/implement/dedupe.js
index 781e8718a..20ba36729 100644
--- a/Sprint-1/implement/dedupe.js
+++ b/Sprint-1/implement/dedupe.js
@@ -1 +1,13 @@
-function dedupe() {}
+function dedupe(array) {
+  const result = [];
+
+  for (const item of array) {
+    if (!result.includes(item)) {
+      result.push(item);
+    }
+  }
+
+  return result;
+}
+
+module.exports = dedupe;
\ No newline at end of file
diff --git a/Sprint-1/implement/dedupe.test.js b/Sprint-1/implement/dedupe.test.js
index d7c8e3d8e..47d93573b 100644
--- a/Sprint-1/implement/dedupe.test.js
+++ b/Sprint-1/implement/dedupe.test.js
@@ -18,11 +18,19 @@ E.g. dedupe([1, 2, 1]) returns [1, 2]
 // 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("it removes duplicate numbers", () => {
+  expect(dedupe([5, 1, 1, 2, 3, 2, 5, 8])).toEqual([5, 1, 2, 3, 8]);
+});
 // Given an array of strings or numbers
 // When passed to the dedupe function
 // Then it should return a new array with duplicates removed while preserving the 
 // first occurrence of each element from the original array.
+test("it removes duplicate strings", () => {
+  expect(dedupe(["a", "a", "a", "b", "b", "c"])).toEqual(["a", "b", "c"]);
+});
\ No newline at end of file
diff --git a/Sprint-1/implement/max.js b/Sprint-1/implement/max.js
index 6dd76378e..0e61d9339 100644
--- a/Sprint-1/implement/max.js
+++ b/Sprint-1/implement/max.js
@@ -1,4 +1,13 @@
 function findMax(elements) {
+  let max = -Infinity;
+
+  for (const element of elements) {
+    if (typeof element === "number" && element > max) {
+      max = element;
+    }
+  }
+
+  return max;
 }
 
-module.exports = findMax;
+module.exports = findMax;
\ No newline at end of file
diff --git a/Sprint-1/implement/max.test.js b/Sprint-1/implement/max.test.js
index 82f18fd88..be2077c7e 100644
--- a/Sprint-1/implement/max.test.js
+++ b/Sprint-1/implement/max.test.js
@@ -16,28 +16,55 @@ 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([])).toBe(-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])).toBe(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 number", () => {
+  expect(findMax([-10, 20, 5, -3])).toBe(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([-10, -5, -20])).toBe(-5);
+});
+
 // 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, 3.7, 2.5])).toBe(3.7);
+});
+
 // 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", () => {
+  expect(findMax(["hey", 10, "hi", 60, 10])).toBe(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(["hello", "world", true, null])).toBe(-Infinity);
+});
\ No newline at end of file
diff --git a/Sprint-1/implement/sum.js b/Sprint-1/implement/sum.js
index 9062aafe3..65e6f4bc6 100644
--- a/Sprint-1/implement/sum.js
+++ b/Sprint-1/implement/sum.js
@@ -1,4 +1,10 @@
 function sum(elements) {
+  return elements.reduce((total, element) => {
+    if (typeof element === "number") {
+      return total + element;
+    }
+    return total;
+  }, 0);
 }
 
-module.exports = sum;
+module.exports = sum;
\ No newline at end of file
diff --git a/Sprint-1/implement/sum.test.js b/Sprint-1/implement/sum.test.js
index dd0a090ca..8e7eee69f 100644
--- a/Sprint-1/implement/sum.test.js
+++ b/Sprint-1/implement/sum.test.js
@@ -13,24 +13,49 @@ 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([])).toBe(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([39])).toBe(39);
+});
+
+
 // 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 containing negative numbers, returns the correct sum", () => {
+  expect(sum([-7, 13, -2])).toBe(4);
+});
+
 // Given an array with decimal/float numbers
 // When passed to the sum function
 // Then it should return the correct total sum
 
+test("given an array containing decimal numbers, returns the correct sum", () => {
+  expect(sum([1.5, 2.5, 3])).toBe(7);
+});
+
+
 // 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 an array containing non-number values, ignores them", () => {
+  expect(sum(["hey", 10, "hi", 60, 20])).toBe(90);
+});
+
 // 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 an array containing only non-number values, returns 0", () => {
+  expect(sum(["hello", true, {}, []])).toBe(0);
+});
\ No newline at end of file
diff --git a/Sprint-1/refactor/includes.js b/Sprint-1/refactor/includes.js
index 29dad81f0..762d868ec 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];
+function includes(list,target) {
+  for (const element of list) {
     if (element === target) {
       return true;
     }