diff --git a/challenges/arrays-callbacks.js b/challenges/arrays-callbacks.js
deleted file mode 100644
index 472ab3e96d..0000000000
--- a/challenges/arrays-callbacks.js
+++ /dev/null
@@ -1,82 +0,0 @@
-// ==== ADVANCED Array Methods ====
-
-// Given this zoo data from around the United States, follow the instructions below.  Use the specific array methods in the requests below to solve the problems.
-
-const zooAnimals = [
-  { animal_name: "Jackal, asiatic", population: 5, scientific_name: "Canis aureus", state: "Kentucky" },
-  { animal_name: "Screamer, southern", population: 1, scientific_name: "Chauna torquata", state: "Alabama" },
-  { animal_name: "White spoonbill", population: 8, scientific_name: "Platalea leucordia", state: "Georgia" },
-  { animal_name: "White-cheeked pintail", population: 1, scientific_name: "Anas bahamensis", state: "Oregon" },
-  { animal_name: "Black-backed jackal", population: 2, scientific_name: "Canis mesomelas", state: "Washington" },
-  { animal_name: "Brolga crane", population: 9, scientific_name: "Grus rubicundus", state: "New Mexico" },
-  { animal_name: "Common melba finch", population: 5, scientific_name: "Pytilia melba", state: "Pennsylvania" },
-  { animal_name: "Pampa gray fox", population: 10, scientific_name: "Pseudalopex gymnocercus", state: "Connecticut" },
-  { animal_name: "Hawk-eagle, crowned", population: 10, scientific_name: "Spizaetus coronatus", state: "Florida" },
-  { animal_name: "Australian pelican", population: 5, scientific_name: "Pelecanus conspicillatus", state: "West Virginia" },
-];
-
-/* Request 1: .forEach()
-
-The zoos want to display both the scientific name and the animal name in front of the habitats. Populate the displayNames array with only the animal_name and scientific_name of each animal. displayNames will be an array of strings, and each string should follow this pattern: "Name: Jackal, asiatic, Scientific: Canis aureus."
-
-*/
-const displayNames = [];
-console.log(displayNames);
-
-/* Request 2: .map()
-
-The zoos need a list of all their animal's names (animal_name only) converted to lower case. Using map, create a new array of strings named lowCaseAnimalNames, each string following this pattern: "jackal, asiatic". Log the resut.
-
-*/
-
-const lowCaseAnimalNames = [];
-console.log(lowCaseAnimalNames);
-
-/* Request 3: .filter() 
-
-The zoos are concerned about animals with a lower population count. Using filter, create a new array of objects called lowPopulationAnimals which contains only the animals with a population less than 5.
-
-*/
-const lowPopulationAnimals = [];
-console.log(lowPopulationAnimals);
-
-/* Request 4: .reduce() 
-
-The zoos need to know their total animal population across the United States. Find the total population from all the zoos using the .reduce() method. Remember the reduce method takes two arguments: a callback (which itself takes two args), and an initial value for the count.
-
-*/
-const populationTotal = 0;
-console.log(populationTotal);
-
-
-// ==== Callbacks ====  
-
-/* Step 1: Create a higher-order function
-  * Create a higher-order function named consume with 3 parameters: a, b and cb
-  * The first two parameters can take any argument (we can pass any value as argument)
-  * The last parameter accepts a callback
-  * The consume function should return the invocation of cb, passing a and b into cb as arguments
-*/
-
-
-/* Step 2: Create several functions to callback with consume();
-  * Create a function named add that returns the sum of two numbers
-  * Create a function named multiply that returns the product of two numbers 
-  * Create a function named greeting that accepts a first and last name and returns "Hello first-name last-name, nice to meet you!"
-*/
-
-
-/* Step 3: Check your work by un-commenting the following calls to consume(): */
-// console.log(consume(2, 2, add)); // 4
-// console.log(consume(10, 16, multiply)); // 160
-// console.log(consume("Mary", "Poppins", greeting)); // Hello Mary Poppins, nice to meet you!
-
-
-
-
-/*
-
-Stretch: If you haven't already, convert your array method callbacks into arrow functions.
-
-*/
-
diff --git a/challenges/classes.js b/challenges/classes.js
index 992e39dc0b..e305cbc168 100644
--- a/challenges/classes.js
+++ b/challenges/classes.js
@@ -1,7 +1,27 @@
 // 1. Copy and paste your prototype in here and refactor into class syntax.
-
+class DuboidMaker{
+constructor(length, width, height){
+    this.height = height;
+    this.width = width;
+    this.length = length;
+}
+ volume(){
+    return this.height * this.weight * this.length;
+  }
+ surfaceArea(){
+    return 2 * (this.length * this.width + this.length * this.height + this.width * this.height);
+  }
+}
+  class ruboid extends DuboidMaker{
+    constructor(length, width, height){
+      super()
+    }
+    
+  }
+  // const cuboid = new CuboidMaker(4,5,5);
+const duboid = new ruboid(4,5,5)
 // Test your volume and surfaceArea methods by uncommenting the logs below:
-// console.log(cuboid.volume()); // 100
-// console.log(cuboid.surfaceArea()); // 130
+console.log(duboid.volume()); // 100
+console.log(duboid.surfaceArea()); // 130
 
 // Stretch Task: Extend the base class CuboidMaker with a sub class called CubeMaker.  Find out the formulas for volume and surface area for cubes and create those methods using the dimension properties from CuboidMaker.  Test your work by logging out your volume and surface area.
\ No newline at end of file
diff --git a/challenges/closure.js b/challenges/closure.js
deleted file mode 100644
index 101d68e553..0000000000
--- a/challenges/closure.js
+++ /dev/null
@@ -1,24 +0,0 @@
-// ==== Closures ==== 
-
-/* Task 1: Study the code below and explain in your own words why nested function can access the variable internal. */
-
-
-const external = "I'm outside the function";
-
-function myFunction() {
-  console.log(external);
-  const internal = "Hello! I'm inside myFunction!";
-
-  function nestedFunction() {
-    console.log(internal);
-  };
-  nestedFunction();
-}
-myFunction();
-
-// Explanation: 
-
-
-/* Task 2: Counter */
-
-/* Create a function called `sumation` that accepts a parameter and uses a counter to return the summation of that number. For example, `summation(4)` should return 10 because 1+2+3+4 is 10. */
diff --git a/challenges/functions.js b/challenges/functions.js
new file mode 100644
index 0000000000..d28e33b0b8
--- /dev/null
+++ b/challenges/functions.js
@@ -0,0 +1,54 @@
+// ==== Callbacks ====  
+
+/* Step 1: Create a higher-order function
+  * Create a higher-order function named consume with 3 parameters: a, b and cb
+  * The first two parameters can take any argument (we can pass any value as argument)
+  * The last parameter accepts a callback
+  * The consume function should return the invocation of cb, passing a and b into cb as arguments
+*/
+function consume (a, b, cb){
+  return cb(a,b);}
+
+
+/* Step 2: Create several functions to callback with consume();
+  * Create a function named add that returns the sum of two numbers
+  * Create a function named multiply that returns the product of two numbers 
+  * Create a function named greeting that accepts a first and last name and returns "Hello first-name last-name, nice to meet you!"
+*/
+function add(a,b){
+  return a + b;
+}
+function multiply(a, b){
+  return a * b;
+}
+function greeting(a, b){
+  return `Hello ${a} ${b}, nice to meet you!`
+};
+
+
+
+/* Step 3: Check your work by un-commenting the following calls to consume(): */
+
+ console.log(consume(2, 2, add)); // 4
+ console.log(consume(10, 16, multiply)); // 160
+ console.log(consume("Mary", "Poppins", greeting)); // Hello Mary Poppins, nice to meet you!
+
+// ==== Closures ==== 
+
+// Explain in your own words why nestedfunction can access the variable internal.
+
+// Explanation: 
+// const can be used from inside of the other function because it is in its scope//
+
+const external = "I'm outside the function";
+
+function myFunction() {
+  console.log(external);
+  const internal = "Hello! I'm inside myFunction!";
+
+  function nestedFunction() {
+    console.log(internal);
+  };
+  nestedFunction();
+}
+myFunction();
diff --git a/challenges/objects-arrays.js b/challenges/objects-arrays.js
new file mode 100644
index 0000000000..8b899d05c3
--- /dev/null
+++ b/challenges/objects-arrays.js
@@ -0,0 +1,134 @@
+// ==== Objects ====
+
+/* 
+  Given the following information about dinosaurs, create 3 objects: 
+  Use this pattern to create your objects: 
+  object name, diet, weight, length, period
+*/
+
+// tyrannosaurus, carnivorous, 7000kg, 12m, Late Cretaceous
+dinos= [
+  {object_name:"tyrannosaurus", diet: "carnivorous", weight:"7000kg", length:"12m", period:"Late Cretaceous", roar: function (){return"RAWERSRARARWERSARARARRRR!"}},
+  {object_name:"stegosaurus", diet:"herbivorous", weight:"2000kg", length:"9m", period:"Late Jurassic"},
+  {object_name:"velociraptor", diet:"carnivorous", weight:"15kg", length:"1.8m", period:"Late Cretaceous"},
+]
+// stegosaurus, herbivorous, 2000kg, 9m, Late Jurassic
+
+// velociraptor, carnivorous, 15kg, 1.8m, Late Cretaceous
+
+// Using your dinosaur objects, log answers to these questions:
+
+// How much did tyrannosaurus weigh?
+console.log(dinos[0].weight);
+
+// What was the diet of a velociraptor?
+console.log(dinos[2].diet);
+
+// How long was a stegosaurus?
+console.log(dinos[1].length);
+
+// What time period did tyrannosaurus live in?
+console.log(dinos[0].period);
+
+
+// Create a new roar method for the tyrannosaurus.  When called, return "RAWERSRARARWERSARARARRRR!" Log the result.
+console.log(dinos[0].roar());
+// ==== Arrays ====
+
+// Given an array of college graduates.  Complete the following requests using any array method you like
+
+const graduates = [
+  { id: 1, first_name: "Cynde", university: "Missouri Southern State College", email: "ctorry0@macromedia.com" },
+  { id: 2, first_name: "Saundra", university: "The School of the Art Institute of Chicago", email: "swhal1@state.gov" },
+  { id: 3, first_name: "Lambert", university: "Marian College", email: "lparham2@techcrunch.com" },
+  { id: 4, first_name: "Modestine", university: "International Medical & Technological University", email: "mdolder3@symantec.com" },
+  { id: 5, first_name: "Chick", university: "Sultan Salahuddin Abdul Aziz Shah Polytechnic", email: "camorts4@google.com.au" },
+  { id: 6, first_name: "Jakob", university: "Fachhochschule Rosenheim, Hochschule für Technik und Wirtschaft", email: "jharken5@spiegel.de" },
+  { id: 7, first_name: "Robbi", university: "Salem University", email: "rbrister6@redcross.org" },
+  { id: 8, first_name: "Colline", university: "Coastal Carolina University", email: "cbrosh7@alibaba.com" },
+  { id: 9, first_name: "Michail", university: "Universidad Católica de Ávila", email: "mrome8@shinystat.com" },
+  { id: 10, first_name: "Hube", university: "Universitat Rovira I Virgili Tarragona", email: "hlethbrig9@foxnews.com" },
+];
+
+/* Request 1: Create a new array called universities that contains all the universities in the graduates array. This will be an array of strings.
+
+Once you have the new array created, log the result. */
+const universities =graduates.map(arr => arr.university)
+console.log(universities);
+
+/* Request 2: Create a new array called contactInfo that contains both first name and email of each student. This will be an array of strings.
+
+The resulting contact information strings should have a space between the first name and the email, like this: 
+"Josh josh@example.com"
+
+Log the result of your new array. */
+const contactInfo = graduates.map((arr) => {return `${arr.first_name} ${arr.email}`})
+console.log(contactInfo);
+
+/* Request 3: Find out how many universities have the string "Uni" included in their name. Create a new array called unisWithUni that contains them all. This will be an array of objects. Log the result. */
+const unisWithUni = [];
+unisWithUni.push(graduates.filter(arr=>arr.university.includes("Uni")));
+console.log(unisWithUni);
+
+
+// ==== ADVANCED Array Methods ====
+
+// Given this zoo data from around the United States, follow the instructions below.  Use the specific array methods in the requests below to solve the problems.
+
+const zooAnimals = [
+  { animal_name: "Jackal, asiatic", population: 5, scientific_name: "Canis aureus", state: "Kentucky" },
+  { animal_name: "Screamer, southern", population: 1, scientific_name: "Chauna torquata", state: "Alabama" },
+  { animal_name: "White spoonbill", population: 8, scientific_name: "Platalea leucordia", state: "Georgia" },
+  { animal_name: "White-cheeked pintail", population: 1, scientific_name: "Anas bahamensis", state: "Oregon" },
+  { animal_name: "Black-backed jackal", population: 2, scientific_name: "Canis mesomelas", state: "Washington" },
+  { animal_name: "Brolga crane", population: 9, scientific_name: "Grus rubicundus", state: "New Mexico" },
+  { animal_name: "Common melba finch", population: 5, scientific_name: "Pytilia melba", state: "Pennsylvania" },
+  { animal_name: "Pampa gray fox", population: 10, scientific_name: "Pseudalopex gymnocercus", state: "Connecticut" },
+  { animal_name: "Hawk-eagle, crowned", population: 10, scientific_name: "Spizaetus coronatus", state: "Florida" },
+  { animal_name: "Australian pelican", population: 5, scientific_name: "Pelecanus conspicillatus", state: "West Virginia" },
+];
+
+/* Request 1: .forEach()
+
+The zoos want to display both the scientific name and the animal name in front of the habitats. Populate the displayNames array with only the animal_name and scientific_name of each animal. displayNames will be an array of strings, and each string should follow this pattern: "Name: Jackal, asiatic, Scientific: Canis aureus."
+
+*/
+const displayNames = [];
+zooAnimals.forEach((arr) => displayNames.push( `Name: ${arr.animal_name}, Scientific: ${arr.scientific_name}`));
+console.log(displayNames);
+
+/* Request 2: .map()
+
+The zoos need a list of all their animal's names (animal_name only) converted to lower case. Using map, create a new array of strings named lowCaseAnimalNames, each string following this pattern: "jackal, asiatic". Log the resut.
+
+*/
+
+const lowCaseAnimalNames = zooAnimals.map(arr => arr.animal_name.toLowerCase())
+console.log(lowCaseAnimalNames);
+
+/* Request 3: .filter() 
+
+The zoos are concerned about animals with a lower population count. Using filter, create a new array of objects called lowPopulationAnimals which contains only the animals with a population less than 5.
+
+*/
+const lowPopulationAnimals = [];
+lowPopulationAnimals.push(zooAnimals.filter(arr =>arr.population < 5))
+console.log(lowPopulationAnimals);
+
+/* Request 4: .reduce() 
+
+The zoos need to know their total animal population across the United States. Find the total population from all the zoos using the .reduce() method. Remember the reduce method takes two arguments: a callback (which itself takes two args), and an initial value for the count.
+
+*/
+
+const populationTotal = zooAnimals.reduce((total, arr,)=>
+   total += arr.population, 0);
+console.log(populationTotal);
+
+
+/*
+
+Stretch: If you haven't already, convert your array method callbacks into arrow functions.
+
+*/
+
diff --git a/challenges/package-lock.json b/challenges/package-lock.json
new file mode 100644
index 0000000000..48e341a095
--- /dev/null
+++ b/challenges/package-lock.json
@@ -0,0 +1,3 @@
+{
+  "lockfileVersion": 1
+}
diff --git a/challenges/prototypes.js b/challenges/prototypes.js
index 4cafc33e95..fe76aab4e8 100644
--- a/challenges/prototypes.js
+++ b/challenges/prototypes.js
@@ -5,29 +5,37 @@
 /* == Step 1: Base Constructor ==
   Create a constructor function named CuboidMaker that accepts properties for length, width, and height
 */
-
-
+function CuboidMaker(length, width, height){
+  this.height = height;
+  this.width = width;
+  this.length = length;
+};
 /* == Step 2: Volume Method ==
   Create a method using CuboidMaker's prototype that returns the volume of a given cuboid's length, width, and height
   
   Formula for cuboid volume: length * width * height
 */
-
-
+CuboidMaker.prototype.volume = function () {
+  return this.height * this.width * this.length;
+};
 /* == Step 3: Surface Area Method ==
   Create another method using CuboidMaker's prototype that returns the surface area of a given cuboid's length, width, and height. 
 
   Formula for cuboid surface area of a cube: 2 * (length * width + length * height + width * height)
 */
 
+CuboidMaker.prototype.surfaceArea = function(){
+  return 2 * (this.length * this.width + this.length * this.height + this.width * this.height);
+}
 
 /* == Step 4: Create a new object that uses CuboidMaker ==
   Create a cuboid object that uses the new keyword to use our CuboidMaker constructor
   Add properties and values of length: 4, width: 5, and height: 5 to cuboid.   
 */
 
+const cuboid = new CuboidMaker(4,5,5);
 // Test your volume and surfaceArea methods by uncommenting the logs below:
-// console.log(cuboid.volume()); // 100
-// console.log(cuboid.surfaceArea()); // 130
+ console.log(cuboid.volume()); // 100
+ console.log(cuboid.surfaceArea()); // 130