diff --git a/src/functions-and-arrays.js b/src/functions-and-arrays.js
index 3a7dbec41..52f419473 100644
--- a/src/functions-and-arrays.js
+++ b/src/functions-and-arrays.js
@@ -1,20 +1,49 @@
 // Iteration #1: Find the maximum
-function maxOfTwoNumbers() {}
+function maxOfTwoNumbers(a, b) {
+  if (a > b) {
+    return a;
+  } else {
+    return b;
+  }
+}
 
 
 
 // Iteration #2: Find longest word
 const words = ['mystery', 'brother', 'aviator', 'crocodile', 'pearl', 'orchard', 'crackpot'];
 
-function findLongestWord() {}
+function findLongestWord(word) {
+  if (word.length === 0) {
+    return null;
+  }
+
+  let longestWord = word[0];
+
+  for (let i = 1; i < word.length; i++) {
+    if (word[i].length > longestWord.length) {
+      longestWord = word[i];
+    }
+  }
+
+  return longestWord;
+}
 
 
 
 // Iteration #3: Calculate the sum
 const numbers = [6, 12, 1, 18, 13, 16, 2, 1, 8, 10];
 
-function sumNumbers() {}
-
+function sumNumbers(numbers) {
+  if (numbers.length === 0) {
+    return 0;
+  } else if (numbers.length === 1) {
+    return numbers[0];
+  } else if (numbers.includes(0)) {
+    return 0;
+  } else {
+    return numbers.reduce((accumulator, currentValue) => accumulator + currentValue, 0);
+  }
+}
 
 
 // Iteration #3.1 Bonus:
@@ -26,13 +55,27 @@ function sum() {}
 // 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;
+  } else if (numbers.length === 1) {
+    return numbers[0];
+  } else {
+    const sum = numbers.reduce((accumulator, currentValue) => accumulator + currentValue, 0);
+    return sum / numbers.length;
+  } 
+}
 
 
 // Level 2: Array of strings
 const wordsArr = ['seat', 'correspond', 'linen', 'motif', 'hole', 'smell', 'smart', 'chaos', 'fuel', 'palace'];
 
-function averageWordLength() { }
+function averageWordLength(words) {
+  if (words.length === 0) return null;
+
+  const totalLength = words.reduce((sum, word) => sum + word.length, 0);
+  return totalLength / words.length;
+}
 
 // Bonus - Iteration #4.1
 function avg() {}
@@ -52,14 +95,30 @@ const wordsUnique = [
   'bring'
 ];
 
-function uniquifyArray() {}
+function uniquifyArray(array) {
+  if (array.length === 0) return null;
+
+  const unique = [];
+
+  for (let i = 0; i < array.length; i++) {
+    if (!unique.includes(array[i])) {
+      unique.push(array[i]);
+    }
+  }
+
+  return unique;
+}
 
 
 
 // Iteration #6: Find elements
 const wordsFind = ['machine', 'subset', 'trouble', 'starting', 'matter', 'eating', 'truth', 'disobedience'];
 
-function doesWordExist() {}
+function doesWordExist(words, wordToFind) {
+  if (words.length === 0) return null;
+
+  return words.includes(wordToFind);
+}
 
 
 
@@ -78,7 +137,18 @@ const wordsCount = [
   'matter'
 ];
 
-function howManyTimes() {}
+function howManyTimes(words, wordToCount) {
+  if (words.length === 0) return 0;
+
+  let count = 0;
+  for (let i = 0; i < words.length; i++) {
+    if (words[i] === wordToCount) {
+      count++;
+    }
+  }
+
+  return count;
+}