diff --git a/src/functions-and-arrays.js b/src/functions-and-arrays.js
index 3a7dbec41..1f674ba96 100644
--- a/src/functions-and-arrays.js
+++ b/src/functions-and-arrays.js
@@ -1,24 +1,76 @@
 // Iteration #1: Find the maximum
-function maxOfTwoNumbers() {}
+function maxOfTwoNumbers(num1, num2) {
+  if (num1 > num2) {
+    return num1;
+  } else if (num1 < num2) {
+    return num2;
+  } else {
+    return num1;
+  }
+}
 
 
 
 // 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 longest = words[0];
+
+  for (let i = 1; i < words.length; i++) {
+    if (words[i].length > longest.length) {
+      longest = words[i];
+    }
+  }
+
+  return longest;
+}
 
 
 
 // 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;
+  }
+
+  let sum = 0;
+
+  for (let i = 0; i < numbers.length; i++) {
+    sum += numbers[i]
+  }
+  return sum
+}
 
 
 
 // Iteration #3.1 Bonus:
-function sum() {}
+function sum(numbers) {
+  if (!numbers.length) return 0;
+
+  let total = 0;
+
+  for (let item of numbers) {
+    if (typeof item === 'number') {
+      total += item;
+    } else if (typeof item === 'string') {
+      total += item.length;
+    } else if (typeof item === 'boolean') {
+      total += item ? 1 : 0;
+    } else {
+      throw new Error("no data type availbale")
+    }
+  }
+
+  return total;
+}
+
+
 
 
 
@@ -26,16 +78,50 @@ function sum() {}
 // Level 1: Array of numbers
 const numbersAvg = [2, 6, 9, 10, 7, 4, 1, 9];
 
-function averageNumbers() {}
+function averageNumbers(numbersAvg) {
+  if ( numbersAvg.length === 0) return null;
+
+  let total = 0;
+
+  for (let num of numbersAvg) {
+    total += num;
+  }
+  return total / numbersAvg.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;
+
+  let average = 0;
+
+  for ( let word of wordsArr) {
+    average += word.length;
+  }
+  return average/wordsArr.length; 
+ }
 
 // Bonus - Iteration #4.1
-function avg() {}
+function avg(wordsArr) {
+  if (wordsArr.length === 0) return null;
+
+  let total = 0;
+
+  for (let item of wordsArr) {
+    if (typeof item === 'number') {
+      total += item;
+    } else if (typeof item === 'string') {
+      total += item.length;
+    } else if (typeof item === 'boolean') {
+      total += item ? 1 : 0;
+    }
+  }
+  return total/wordsArr.length;
+}
+
 
 // Iteration #5: Unique arrays
 const wordsUnique = [
@@ -52,15 +138,29 @@ const wordsUnique = [
   'bring'
 ];
 
-function uniquifyArray() {}
+function uniquifyArray(wordsUnique) {
+  if (wordsUnique.length === 0) return null;
+
+let newWordsUnique = [];
+
+for (let word of wordsUnique) {
+  if(!newWordsUnique.includes(word)) {
+    newWordsUnique.push(word);
+  }
+}
+return newWordsUnique;
+}
 
 
 
 // Iteration #6: Find elements
 const wordsFind = ['machine', 'subset', 'trouble', 'starting', 'matter', 'eating', 'truth', 'disobedience'];
 
-function doesWordExist() {}
+function doesWordExist(wordsFind, wordToSearch) {
+  if (wordsFind.length === 0) return null;
 
+  return wordsFind.includes(wordToSearch);
+}
 
 
 // Iteration #7: Count repetition
@@ -78,7 +178,18 @@ const wordsCount = [
   'matter'
 ];
 
-function howManyTimes() {}
+function howManyTimes(wordsCount, wordToCount) {
+  if (wordsCount.length === 0) return 0;
+
+  let count = 0;
+
+  for (let word of wordsCount) {
+    if (word === wordToCount) {
+      count++;
+    }
+  }
+  return count;
+}