diff --git a/Sprint-1/fix/median.js b/Sprint-1/fix/median.js
index b22590bc6..17865dfac 100644
--- a/Sprint-1/fix/median.js
+++ b/Sprint-1/fix/median.js
@@ -6,9 +6,15 @@
 // 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 nums = list.filter((n) => typeof n === "number" && !isNaN(n));
+  if (!nums.length) return null;
+
+  const sorted = nums.slice().sort((a, b) => a - b);
+  const mid = Math.floor(sorted.length / 2);
+
+  return sorted.length % 2 ? sorted[mid] : (sorted[mid - 1] + sorted[mid]) / 2;
 }
 
 module.exports = calculateMedian;
diff --git a/Sprint-1/implement/dedupe.js b/Sprint-1/implement/dedupe.js
index 781e8718a..bfedf4ed4 100644
--- a/Sprint-1/implement/dedupe.js
+++ b/Sprint-1/implement/dedupe.js
@@ -1 +1,17 @@
-function dedupe() {}
+function dedupe(arr) {
+  if (!Array.isArray(arr)) return [];
+
+  const seen = new Set();
+  const result = [];
+
+  for (const item of arr) {
+    if (!seen.has(item)) {
+      seen.add(item);
+      result.push(item);
+    }
+  }
+
+  return result;
+}
+
+module.exports = dedupe;
diff --git a/Sprint-1/implement/max.js b/Sprint-1/implement/max.js
index 6dd76378e..7cdc5c6bd 100644
--- a/Sprint-1/implement/max.js
+++ b/Sprint-1/implement/max.js
@@ -1,4 +1,11 @@
 function findMax(elements) {
+  if (!Array.isArray(elements)) return -Infinity;
+
+  const nums = elements.filter((n) => typeof n === "number" && !isNaN(n));
+
+  if (nums.length === 0) return -Infinity;
+
+  return nums.reduce((max, curr) => (curr > max ? curr : max), -Infinity);
 }
 
 module.exports = findMax;
diff --git a/Sprint-1/implement/max.test.js b/Sprint-1/implement/max.test.js
index 82f18fd88..760bd1fb5 100644
--- a/Sprint-1/implement/max.test.js
+++ b/Sprint-1/implement/max.test.js
@@ -16,28 +16,44 @@ 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([8])).toBe(8);
+  });
 // Given an array with both positive and negative numbers
 // When passed to the max function
 // Then it should return the largest number overall
-
+test("returns the largest number from positive and negative numbers", () => {
+    expect(findMax([5, -9, 25, 8, -12])).toBe(25);
+  });
 // Given an array with just negative numbers
 // When passed to the max function
 // Then it should return the closest one to zero
-
+test("returns the closest to zero for all negative numbers", () => {
+    expect(findMax([-10, -2, -25])).toBe(-2);
+  });
 // Given an array with decimal numbers
 // When passed to the max function
 // Then it should return the largest decimal number
-
+test("returns the largest decimal number", () => {
+    expect(findMax([1.9, 2.9, 2.5])).toBe(2.9);
+  });
 // 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("ignores non-numeric values", () => {
+    expect(findMax(["hey", 10, "hello", 50, 20])).toBe(50);
+  });
 
 // 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("returns -Infinity for only non-number values", () => {
+    expect(findMax(["a", null, undefined])).toBe(-Infinity);
+  });
diff --git a/Sprint-1/implement/sum.js b/Sprint-1/implement/sum.js
index 9062aafe3..10f1fbe0f 100644
--- a/Sprint-1/implement/sum.js
+++ b/Sprint-1/implement/sum.js
@@ -1,4 +1,15 @@
 function sum(elements) {
+  if (!Array.isArray(elements)) return 0;
+
+  let total = 0;
+
+  for (const item of elements) {
+    if (typeof item === "number") {
+      total += item;
+    }
+  }
+
+  return total;
 }
 
 module.exports = sum;
diff --git a/Sprint-1/package-lock.json b/Sprint-1/package-lock.json
index 83e427d0b..743bde1f7 100644
--- a/Sprint-1/package-lock.json
+++ b/Sprint-1/package-lock.json
@@ -2125,9 +2125,9 @@
       }
     },
     "node_modules/istanbul-lib-instrument/node_modules/semver": {
-      "version": "7.6.3",
-      "resolved": "https://registry.npmjs.org/semver/-/semver-7.6.3.tgz",
-      "integrity": "sha512-oVekP1cKtI+CTDvHWYFUcMtsK/00wmAEfyqKfNdARm8u1wNVhSgaX7A8d4UuIlUI5e84iEwOhs7ZPYRmzU9U6A==",
+      "version": "7.7.4",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-7.7.4.tgz",
+      "integrity": "sha512-vFKC2IEtQnVhpT78h1Yp8wzwrf8CM+MzKMHGJZfBtzhZNycRFnXsHk6E5TxIkkMsgNS7mdX3AGB7x2QM2di4lA==",
       "dev": true,
       "license": "ISC",
       "bin": {
@@ -2664,9 +2664,9 @@
       }
     },
     "node_modules/jest-snapshot/node_modules/semver": {
-      "version": "7.6.3",
-      "resolved": "https://registry.npmjs.org/semver/-/semver-7.6.3.tgz",
-      "integrity": "sha512-oVekP1cKtI+CTDvHWYFUcMtsK/00wmAEfyqKfNdARm8u1wNVhSgaX7A8d4UuIlUI5e84iEwOhs7ZPYRmzU9U6A==",
+      "version": "7.7.4",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-7.7.4.tgz",
+      "integrity": "sha512-vFKC2IEtQnVhpT78h1Yp8wzwrf8CM+MzKMHGJZfBtzhZNycRFnXsHk6E5TxIkkMsgNS7mdX3AGB7x2QM2di4lA==",
       "dev": true,
       "license": "ISC",
       "bin": {
@@ -2898,9 +2898,9 @@
       }
     },
     "node_modules/make-dir/node_modules/semver": {
-      "version": "7.6.3",
-      "resolved": "https://registry.npmjs.org/semver/-/semver-7.6.3.tgz",
-      "integrity": "sha512-oVekP1cKtI+CTDvHWYFUcMtsK/00wmAEfyqKfNdARm8u1wNVhSgaX7A8d4UuIlUI5e84iEwOhs7ZPYRmzU9U6A==",
+      "version": "7.7.4",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-7.7.4.tgz",
+      "integrity": "sha512-vFKC2IEtQnVhpT78h1Yp8wzwrf8CM+MzKMHGJZfBtzhZNycRFnXsHk6E5TxIkkMsgNS7mdX3AGB7x2QM2di4lA==",
       "dev": true,
       "license": "ISC",
       "bin": {
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;
     }