solution as far as I could get

src/functions-and-arrays.js

@@ -1,38 +1,79 @@
 // Iteration #1: Find the maximum
-function maxOfTwoNumbers() {}
+function maxOfTwoNumbers(a, b) {
+  if(a > b) {
+    return a
+  } else { 
+    return b }
+}
+maxOfTwoNumbers(3, 5);
 
 
 
 // Iteration #2: Find longest word
-const words = ['mystery', 'brother', 'aviator', 'crocodile', 'pearl', 'orchard', 'crackpot'];
-
-function findLongestWord() {}
-
-
+const words = ['seat', 'correspond', 'linen', 'motif', 'hole', 'smell', 'smart', 'chaos', 'fuel', 'palace'];
+
+function findLongestWord(arrayOfWords) {
+  let longestWord = arrayOfWords[0];
+  for (let i=0; i<arrayOfWords.length; i++) {
+    if (arrayOfWords[i].length > longestWord.length) {
+      longestWord = arrayOfWords[i]
+    }
+  }
+  return longestWord;
+}
 
-// Iteration #3: Calculate the sum
-const numbers = [6, 12, 1, 18, 13, 16, 2, 1, 8, 10];
+// Iteration #3: Calculate the sum 
+const myArray = [6, 12, 1, 18, 13, 16, 2, 1, 8, 12];
 
-function sumNumbers() {}
 
+function sumNumbers(numbers) {
+  if(myArray == []) {
+    result === 0
+  }
+  let result = 0;
+  for(let i = 0; i<numbers.length; i++) {
+      console.log(numbers[i]);
+      result = result + numbers[i];
+  }
+  return result;
+}
+console.log(sumNumbers(myArray));
 
 
 // Iteration #3.1 Bonus:
 function sum() {}
 
 
-
 // Iteration #4: Calculate the average
 // Level 1: Array of numbers
-const numbersAvg = [2, 6, 9, 10, 7, 4, 1, 9];
 
-function averageNumbers() {}
+function averageNumbers(_newinput) {
+  if(_newinput == 0) {
+    return null;
+  } else if (_newinput.length == 1) {
+    return _newinput[0];
+  } else {
+let total = 0;
+for (let i = 0; i < numbersAvg.length; i++) {
+    total += numbersAvg[i];
+  }
+}
+  let avg = total / numbersAvg.length;
+  return avg;
+}
 
 
 // Level 2: Array of strings
-const wordsArr = ['seat', 'correspond', 'linen', 'motif', 'hole', 'smell', 'smart', 'chaos', 'fuel', 'palace'];
-
-function averageWordLength() { }
+function averageWordLength(wordsArr) {
+  if(wordsArr == 0) {
+    return null;
+  } else if (wordsArr.length == 1) {
+    return wordsArr[0];
+  } else {
+}
+let wordsAvg = wordsArr.join("").length / wordsArr.length;
+return wordsAvg;
+}
 
 // Bonus - Iteration #4.1
 function avg() {}
@@ -52,19 +93,47 @@ const wordsUnique = [
   'bring'
 ];
 
-function uniquifyArray() {}
 
+function uniquifyArray(arr) {
+let newWordArray = [];
+if (arr.length === 0) {
+  return null;
+}
+for(let i=0; i<arr.length; i++) {
+  if(newWordArray.indexOf(arr[i]) === -1) { //As a rule,tThe first index of the element in the array; -1 if not found. We use this
+    //insight to evaluate, as we loop through, that we do not take another element in that is already present in NewWordArray
+  newWordArray.push(arr[i]);    //Pushing it in the new array if it fulfills the IF statement
+  }
+}
+return newWordArray;
+}
+//Approach
+//loop in wordsUnique
+//push into new array if it's not already there
+//indexOf in the new array is -1
 
 
 // Iteration #6: Find elements
 const wordsFind = ['machine', 'subset', 'trouble', 'starting', 'matter', 'eating', 'truth', 'disobedience'];
 
-function doesWordExist() {}
-
+function doesWordExist(wordsFind) {
+let newWordArr = [];
+if (wordsFind.length === 0) {
+    return null;
+}
+for(let i=0; i<wordsFind.length; i++) {
+    if (wordsFind[i] == newWordArr[i]) {
+      return false;
+    } else {
+      return true;
+    }
+  }
+  console.log(doesWordExist(wordsFind));
+}
 
 
 // Iteration #7: Count repetition
-const wordsCount = [
+const timesArr = [
   'machine',
   'matter',
   'subset',
@@ -78,9 +147,16 @@ const wordsCount = [
   'matter'
 ];
 
-function howManyTimes() {}
-
-
+function howManyTimes(timesArr) {
+  let count = [];
+  for(let i=0; i<timesArr.length; i++) {
+    if(timesArr.indexOf(count[i]) === -1) {
+      count.push(timesArr[i]);
+    }
+  }
+  console.log(count);
+}
+
 
 // Iteration #8: Bonus
 const matrix = [