diff --git a/README.md b/README.md
index ab9fadd9a..913e656b4 100644
--- a/README.md
+++ b/README.md
@@ -237,7 +237,7 @@ Do this in the form of a function `uniquifyArray` that receives an array of word
 You can use the following array to test your solution:
 
 ```javascript
-const words = [
+const words = [ 
   'crab',
   'poison',
   'contagious',
diff --git a/src/functions-and-arrays.js b/src/functions-and-arrays.js
index 3a7dbec41..5a2f330ad 100644
--- a/src/functions-and-arrays.js
+++ b/src/functions-and-arrays.js
@@ -1,41 +1,122 @@
 // Iteration #1: Find the maximum
-function maxOfTwoNumbers() {}
-
-
+function maxOfTwoNumbers(x, y) {
+  return x > y ? x : y;
+}
 
 // Iteration #2: Find longest word
-const words = ['mystery', 'brother', 'aviator', 'crocodile', 'pearl', 'orchard', 'crackpot'];
-
-function findLongestWord() {}
-
+const words = [
+  'mystery',
+  'brother',
+  'aviator',
+  'crocodile',
+  'pearl',
+  'orchard',
+  'crackpot',
+];
 
+function findLongestWord(words) {
+  //check if the array is empty
+  if (words.length === 0) {
+    return null;
+  }
+  //initialize longest with the first element of the array
+  let longest = words[0];
+  //iterate through the array from the second word
+  for (let i = 1; i < words.length; i++) {
+    if (words[i].length > longest.length) {
+      //here is where longest gets updated
+      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) {
+  let sum = 0;
+  for (let i = 0; i < numbers.length; i++) {
+    sum += numbers[i];
+  }
+  return sum;
+}
 
 // Iteration #3.1 Bonus:
-function sum() {}
-
-
+function sum(mixedArr) {
+  sumLength = 0;
+
+  for (let i = 0; i < mixedArr.length; i++) {
+    const value = mixedArr[i];
+
+    if (typeof value === 'string') {
+      sumLength += value.length;
+    } else if (typeof value === 'number') {
+      sumLength += value;
+    } else if (typeof value === 'boolean') {
+      sumLength += value ? 1 : 0;
+    } else if (typeof value === 'object') {
+      throw new Error('not a primitive data type');
+    }
+  }
+
+  return sumLength;
+}
 
 // Iteration #4: Calculate the average
 // 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;
+  }
+  //here I reuse the function created above
+  const sum = sumNumbers(numbersAvg);
 
+  const avg = sum / numbersAvg.length;
+  return avg;
+}
 
 // Level 2: Array of strings
-const wordsArr = ['seat', 'correspond', 'linen', 'motif', 'hole', 'smell', 'smart', 'chaos', 'fuel', 'palace'];
+const wordsArr = [
+  'seat',
+  'correspond',
+  'linen',
+  'motif',
+  'hole',
+  'smell',
+  'smart',
+  'chaos',
+  'fuel',
+  'palace',
+];
 
-function averageWordLength() { }
+function averageWordLength(wordsArr) {
+  if (wordsArr.length === 0) {
+    return null;
+  }
+  //get the sum of the lengths
+  let sumLength = 0;
+
+  for (let i = 0; i < wordsArr.length; i++) {
+    sumLength = wordsArr[i].length;
+  }
+  const avgLength = sumLength / wordsArr.length;
+  return avgLength;
+}
 
 // Bonus - Iteration #4.1
-function avg() {}
+function avg(mixedArr) {
+  if (mixedArr.length === 0) {
+    return null;
+  }
+  //here I reuse the function created above
+  const total = sum(mixedArr);
+
+  const average = total / mixedArr.length;
+  return average;
+}
 
 // Iteration #5: Unique arrays
 const wordsUnique = [
@@ -49,19 +130,80 @@ const wordsUnique = [
   'poison',
   'communion',
   'simple',
-  'bring'
+  'bring',
 ];
 
-function uniquifyArray() {}
-
+function uniquifyArray(wordsUnique) {
+  if (wordsUnique.length === 0) {
+    return null;
+  }
+  const uniqueArr = [];
+
+  for (let i = 0; i < wordsUnique.length; i++) {
+    let word = wordsUnique[i];
+    if (uniqueArr.indexOf(word) === -1) {
+      //here is where I build the new array
+      uniqueArr.push(word);
+    }
+  }
+  return uniqueArr;
+}
 
+//test example
+const words1 = [
+  'crab',
+  'poison',
+  'contagious',
+  'simple',
+  'bring',
+  'sharp',
+  'playground',
+  'poison',
+  'communion',
+  'simple',
+  'bring',
+];
+const only = uniquifyArray(words1);
+console.log(only);
 
 // Iteration #6: Find elements
-const wordsFind = ['machine', 'subset', 'trouble', 'starting', 'matter', 'eating', 'truth', 'disobedience'];
+const wordsFind = [
+  'machine',
+  'subset',
+  'trouble',
+  'starting',
+  'matter',
+  'eating',
+  'truth',
+  'disobedience',
+];
 
-function doesWordExist() {}
+function doesWordExist(wordsFind, wordsSearch) {
+  if (wordsFind.length === 0) {
+    return null;
+  } else {
+    if (wordsFind.includes(wordsSearch)) {
+      return true;
+    } else {
+      return false;
+    }
+  }
+}
 
+//test case
 
+const wordsF = [
+  'machine',
+  'subset',
+  'trouble',
+  'starting',
+  'matter',
+  'eating',
+  'truth',
+  'disobedience',
+];
+const wordsFF = doesWordExist('machine', 'machine');
+console.log(wordsFF);
 
 // Iteration #7: Count repetition
 const wordsCount = [
@@ -75,42 +217,92 @@ const wordsCount = [
   'matter',
   'truth',
   'disobedience',
-  'matter'
+  'matter',
 ];
 
-function howManyTimes() {}
-
-
+function howManyTimes(wordsCount, wordSearch) {
+  if (wordsCount.length === 0) {
+    return 0;
+  }
+  let times = 0;
+  for (let i = 0; i < wordsCount.length; i++) {
+    if (wordsCount[i] === wordSearch) {
+      times++;
+    }
+  }
+  return times;
+}
+const timestest = howManyTimes(wordsCount, 'machine');
+console.log(timestest);
 
 // Iteration #8: Bonus
 const matrix = [
   [8, 2, 22, 97, 38, 15, 0, 40, 0, 75, 4, 5, 7, 78, 52, 12, 50, 77, 91, 8],
-  [49, 49, 99, 40, 17, 81, 18, 57, 60, 87, 17, 40, 98, 43, 69, 48, 4, 56, 62, 0],
-  [81, 49, 31, 73, 55, 79, 14, 29, 93, 71, 40, 67, 53, 88, 30, 3, 49, 13, 36, 65],
+  [
+    49, 49, 99, 40, 17, 81, 18, 57, 60, 87, 17, 40, 98, 43, 69, 48, 4, 56, 62,
+    0,
+  ],
+  [
+    81, 49, 31, 73, 55, 79, 14, 29, 93, 71, 40, 67, 53, 88, 30, 3, 49, 13, 36,
+    65,
+  ],
   [52, 70, 95, 23, 4, 60, 11, 42, 69, 24, 68, 56, 1, 32, 56, 71, 37, 2, 36, 91],
-  [22, 31, 16, 71, 51, 67, 63, 89, 41, 92, 36, 54, 22, 40, 40, 28, 66, 33, 13, 80],
-  [24, 47, 32, 60, 99, 3, 45, 2, 44, 75, 33, 53, 78, 36, 84, 20, 35, 17, 12, 50],
-  [32, 98, 81, 28, 64, 23, 67, 10, 26, 38, 40, 67, 59, 54, 70, 66, 18, 38, 64, 70],
-  [67, 26, 20, 68, 2, 62, 12, 20, 95, 63, 94, 39, 63, 8, 40, 91, 66, 49, 94, 21],
-  [24, 55, 58, 5, 66, 73, 99, 26, 97, 17, 78, 78, 96, 83, 14, 88, 34, 89, 63, 72],
+  [
+    22, 31, 16, 71, 51, 67, 63, 89, 41, 92, 36, 54, 22, 40, 40, 28, 66, 33, 13,
+    80,
+  ],
+  [
+    24, 47, 32, 60, 99, 3, 45, 2, 44, 75, 33, 53, 78, 36, 84, 20, 35, 17, 12,
+    50,
+  ],
+  [
+    32, 98, 81, 28, 64, 23, 67, 10, 26, 38, 40, 67, 59, 54, 70, 66, 18, 38, 64,
+    70,
+  ],
+  [
+    67, 26, 20, 68, 2, 62, 12, 20, 95, 63, 94, 39, 63, 8, 40, 91, 66, 49, 94,
+    21,
+  ],
+  [
+    24, 55, 58, 5, 66, 73, 99, 26, 97, 17, 78, 78, 96, 83, 14, 88, 34, 89, 63,
+    72,
+  ],
   [21, 36, 23, 9, 75, 0, 76, 44, 20, 45, 35, 14, 0, 61, 33, 97, 34, 31, 33, 95],
   [78, 17, 53, 28, 22, 75, 31, 67, 15, 94, 3, 80, 4, 62, 16, 14, 9, 53, 56, 92],
-  [16, 39, 5, 42, 96, 35, 31, 47, 55, 58, 88, 24, 0, 17, 54, 24, 36, 29, 85, 57],
+  [
+    16, 39, 5, 42, 96, 35, 31, 47, 55, 58, 88, 24, 0, 17, 54, 24, 36, 29, 85,
+    57,
+  ],
   [86, 56, 0, 48, 35, 71, 89, 7, 5, 44, 44, 37, 44, 60, 21, 58, 51, 54, 17, 58],
-  [19, 80, 81, 68, 5, 94, 47, 69, 28, 73, 92, 13, 86, 52, 17, 77, 4, 89, 55, 40],
+  [
+    19, 80, 81, 68, 5, 94, 47, 69, 28, 73, 92, 13, 86, 52, 17, 77, 4, 89, 55,
+    40,
+  ],
   [4, 52, 8, 83, 97, 35, 99, 16, 7, 97, 57, 32, 16, 26, 26, 79, 33, 27, 98, 66],
-  [88, 36, 68, 87, 57, 62, 20, 72, 3, 46, 33, 67, 46, 55, 12, 32, 63, 93, 53, 69],
-  [4, 42, 16, 73, 38, 25, 39, 11, 24, 94, 72, 18, 8, 46, 29, 32, 40, 62, 76, 36],
-  [20, 69, 36, 41, 72, 30, 23, 88, 34, 62, 99, 69, 82, 67, 59, 85, 74, 4, 36, 16],
-  [20, 73, 35, 29, 78, 31, 90, 1, 74, 31, 49, 71, 48, 86, 81, 16, 23, 57, 5, 54],
-  [1, 70, 54, 71, 83, 51, 54, 69, 16, 92, 33, 48, 61, 43, 52, 1, 89, 19, 67, 48]
+  [
+    88, 36, 68, 87, 57, 62, 20, 72, 3, 46, 33, 67, 46, 55, 12, 32, 63, 93, 53,
+    69,
+  ],
+  [
+    4, 42, 16, 73, 38, 25, 39, 11, 24, 94, 72, 18, 8, 46, 29, 32, 40, 62, 76,
+    36,
+  ],
+  [
+    20, 69, 36, 41, 72, 30, 23, 88, 34, 62, 99, 69, 82, 67, 59, 85, 74, 4, 36,
+    16,
+  ],
+  [
+    20, 73, 35, 29, 78, 31, 90, 1, 74, 31, 49, 71, 48, 86, 81, 16, 23, 57, 5,
+    54,
+  ],
+  [
+    1, 70, 54, 71, 83, 51, 54, 69, 16, 92, 33, 48, 61, 43, 52, 1, 89, 19, 67,
+    48,
+  ],
 ];
 
 function greatestProduct() {}
 
-
-
-
 // The following is required to make unit tests work.
 /* Environment setup. Do not modify the below code. */
 if (typeof module !== 'undefined') {
@@ -125,6 +317,6 @@ if (typeof module !== 'undefined') {
     uniquifyArray,
     doesWordExist,
     howManyTimes,
-    greatestProduct
+    greatestProduct,
   };
 }