diff --git a/src/functions-and-arrays.js b/src/functions-and-arrays.js
index 3a7dbec..b0e394f 100644
--- a/src/functions-and-arrays.js
+++ b/src/functions-and-arrays.js
@@ -1,41 +1,74 @@
 // Iteration #1: Find the maximum
-function maxOfTwoNumbers() {}
-
-
+function maxOfTwoNumbers() {
+  return a > b ? a : b;
+}
 
 // Iteration #2: Find longest word
 const words = ['mystery', 'brother', 'aviator', 'crocodile', 'pearl', 'orchard', 'crackpot'];
 
-function findLongestWord() {}
-
-
+function findLongestWord(words) {
+  if (words.length === 0) return null;
+  let longestWord = words[0];
+  for (let word of words) {
+    if (word.length > longestWord.length) {
+      longestWord = word;
+    }
+  }
+  return longestWord;
+}
 
 // Iteration #3: Calculate the sum
 const numbers = [6, 12, 1, 18, 13, 16, 2, 1, 8, 10];
 
-function sumNumbers() {}
-
-
+function sumNumbers() {
+  return numbers.reduce((acc, curr) => acc + curr, 0);
+}
 
 // Iteration #3.1 Bonus:
-function sum() {}
-
-
+function sum(mixedArray) {
+  return mixedArray.reduce((acc, curr) => {
+    if (typeof curr === 'number') {
+      return acc + curr;
+    } else if (typeof curr === 'string') {
+      return acc + curr.length;
+    } else {
+      return acc; // ignore other types
+    }
+  }, 0);
+}
 
 // Iteration #4: Calculate the average
 // Level 1: Array of numbers
 const numbersAvg = [2, 6, 9, 10, 7, 4, 1, 9];
 
-function averageNumbers() {}
-
+function averageNumbers(numbers) {
+  if (numbers.length === 0) return null;
+  return sumNumbers(numbers) / numbers.length;
+}
 
 // Level 2: Array of strings
 const wordsArr = ['seat', 'correspond', 'linen', 'motif', 'hole', 'smell', 'smart', 'chaos', 'fuel', 'palace'];
 
-function averageWordLength() { }
+function averageWordLength(wordsArr) {
+  if (wordsArr.length === 0) return null;
+  const totalLength = wordsArr.reduce((acc, word) => acc + word.length, 0);
+  return totalLength / wordsArr.length;
+}
 
 // Bonus - Iteration #4.1
-function avg() {}
+function avg(arr) {
+  if (arr.length === 0) return null;
+  const total = arr.reduce((acc, item) => {
+    if (typeof item === 'number') {
+      return acc + item;
+    } else if (typeof item === 'string') {
+      return acc + item.length;
+    }
+    return acc;
+  }, 0);
+
+  return total / arr.length;
+}
 
 // Iteration #5: Unique arrays
 const wordsUnique = [
@@ -52,16 +85,16 @@ const wordsUnique = [
   'bring'
 ];
 
-function uniquifyArray() {}
-
-
+function uniquifyArray(wordsUnique) {
+  return [...new Set(wordsUnique)];
+}
 
 // Iteration #6: Find elements
 const wordsFind = ['machine', 'subset', 'trouble', 'starting', 'matter', 'eating', 'truth', 'disobedience'];
 
-function doesWordExist() {}
-
-
+function doesWordExist(wordsFind, word) {
+  return wordsFind.includes(word);
+}
 
 // Iteration #7: Count repetition
 const wordsCount = [
@@ -78,9 +111,9 @@ const wordsCount = [
   'matter'
 ];
 
-function howManyTimes() {}
-
-
+function howManyTimes(wordsCount, word) {
+  return wordsCount.filter((w) => w === word).length;
+}
 
 // Iteration #8: Bonus
 const matrix = [
@@ -106,10 +139,44 @@ const matrix = [
   [1, 70, 54, 71, 83, 51, 54, 69, 16, 92, 33, 48, 61, 43, 52, 1, 89, 19, 67, 48]
 ];
 
-function greatestProduct() {}
-
-
-
+function greatestProduct(matrix) {
+  let maxProduct = 0;
+
+  const rows = matrix.length;
+  const cols = matrix[0].length;
+
+  for (let i = 0; i < rows; i++) {
+    for (let j = 0; j < cols; j++) {
+      // Check right (horizontal)
+      if (j < cols - 3) {
+        const horizontalProduct = matrix[i][j] * matrix[i][j + 1] * matrix[i][j + 2] * matrix[i][j + 3];
+        maxProduct = Math.max(maxProduct, horizontalProduct);
+      }
+
+      // Check down (vertical)
+      if (i < rows - 3) {
+        const verticalProduct = matrix[i][j] * matrix[i + 1][j] * matrix[i + 2][j] * matrix[i + 3][j];
+        maxProduct = Math.max(maxProduct, verticalProduct);
+      }
+
+      // Check diagonal down-right
+      if (i < rows - 3 && j < cols - 3) {
+        const diagonalDownRightProduct =
+          matrix[i][j] * matrix[i + 1][j + 1] * matrix[i + 2][j + 2] * matrix[i + 3][j + 3];
+        maxProduct = Math.max(maxProduct, diagonalDownRightProduct);
+      }
+
+      // Check diagonal down-left
+      if (i < rows - 3 && j > 2) {
+        const diagonalDownLeftProduct =
+          matrix[i][j] * matrix[i + 1][j - 1] * matrix[i + 2][j - 2] * matrix[i + 3][j - 3];
+        maxProduct = Math.max(maxProduct, diagonalDownLeftProduct);
+      }
+    }
+  }
+
+  return maxProduct;
+}
 
 // The following is required to make unit tests work.
 /* Environment setup. Do not modify the below code. */