diff --git a/challenges/classes.js b/challenges/classes.js
index 992e39dc0b..eb63973b94 100644
--- a/challenges/classes.js
+++ b/challenges/classes.js
@@ -1,7 +1,47 @@
 // 1. Copy and paste your prototype in here and refactor into class syntax.
+class  CuboidMaker{
+    constructor(attr){
+    this.length = attr.length,
+    this.width = attr.width,
+    this.height = attr.height;
+  }
+  volume(){
+      return this.length * this. width * this.height;
+  }
+  surfaceArea(){
+      return 2 * (this.length * this.width + this.length * this.height + this.width * this.height)
+  }
+} 
 
+class CubeMaker{
+    constructor(attr){
+    this.length = attr.length,
+    this.width = attr.width,
+    this.height = attr.height;
+    }
+    surfaceArea(){
+        return 6 * (this.length * this.height)
+    }
+    volume(){
+        return (this.length * this.length * this.length)
+    }
+}
+
+const cuboid = new CuboidMaker ({
+    length:4,
+    width: 5,
+    height: 5
+})
+
+const cube = new CubeMaker({
+    length:5,
+    width:5,
+    height: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
+console.log(cube.volume());
+console.log(cube.surfaceArea());
 
 // 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/functions.js b/challenges/functions.js
index 6e3688bfcc..10c2efcb41 100644
--- a/challenges/functions.js
+++ b/challenges/functions.js
@@ -6,6 +6,9 @@
   * 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();
@@ -13,19 +16,28 @@
   * 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!
+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: 
+// Explanation: nestedFunction can access the var internal because they are both within the same scope and therefore have access to the same variables
 
 
 const external = "I'm outside the function";
diff --git a/challenges/objects-arrays.js b/challenges/objects-arrays.js
index 659e3e149c..e33acce589 100644
--- a/challenges/objects-arrays.js
+++ b/challenges/objects-arrays.js
@@ -6,29 +6,30 @@
   object name, diet, weight, length, period
 */
 
-// tyrannosaurus, carnivorous, 7000kg, 12m, Late Cretaceous
+let trex = {name: 'tyrannosaurus', diet: 'carnivorous', weight: '7000kg', length: '12m', period: 'Late Cretaceous', roar: function() {return `RAWERSRARARWERSARARARRRR`} };
 
-// stegosaurus, herbivorous, 2000kg, 9m, Late Jurassic
+let stego = { name: 'stegosaurus', diet: 'herbivorous', weight: '2000kg', length: '9m', period: 'Late Jurassic'};
+
+let veloci = {name: 'velociraptor', diet:'carnivorous', weight: '15kg', length: '1.8m', period: 'Late Cretaceous'}
 
-// velociraptor, carnivorous, 15kg, 1.8m, Late Cretaceous
 
 // Using your dinosaur objects, log answers to these questions:
 
 // How much did tyrannosaurus weigh?
-console.log();
+console.log(trex.weight);
 
 // What was the diet of a velociraptor?
-console.log();
+console.log(veloci.diet);
 
 // How long was a stegosaurus?
-console.log();
+console.log(stego.length);
 
 // What time period did tyrannosaurus live in?
-console.log();
+console.log(trex.period);
 
 
 // Create a new roar method for the tyrannosaurus.  When called, return "RAWERSRARARWERSARARARRRR!" Log the result.
-console.log();
+console.log(trex.roar());
 
 
 // ==== Arrays ====
@@ -52,7 +53,10 @@ const graduates = [
 
 Once you have the new array created, sort the universities alphabetically and log the result. */
 const universities = [];
-console.log(universities);
+for(let i = 0; i < graduates.length; i++){
+  universities.push(graduates[i].university)
+}
+console.log(universities.sort());
 
 /* 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.
 
@@ -61,10 +65,19 @@ The resulting contact information strings should have a space between the first
 
 Log the result of your new array. */
 const contactInfo = [];
+for(let i = 0; i < graduates.length; i++){
+  contactInfo.push(graduates[i].first_name, graduates[i].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 = [];
+for(let i =0;i < graduates.length; i++){
+  let uniSort = graduates[i].university;
+  if(uniSort.includes("Uni")){
+      unisWithUni.push(uniSort)
+  }
+}
 console.log(unisWithUni);
 
 
@@ -91,6 +104,9 @@ The zoos want to display both the scientific name and the animal name in front o
 
 */
 const displayNames = [];
+for(let i = 0; i < zooAnimals.length; i++){
+  displayNames.push(`Name: ${zooAnimals[i].animal_name}, Scientific: ${zooAnimals[i].scientific_name}`)
+};
 console.log(displayNames);
 
 /* Request 2: .map()
@@ -100,6 +116,9 @@ The zoos need a list of all their animal's names (animal_name only) converted to
 */
 
 const lowCaseAnimalNames = [];
+zooAnimals.map(animal => {
+  lowCaseAnimalNames.push(animal.animal_name.toLowerCase())
+})
 console.log(lowCaseAnimalNames);
 
 /* Request 3: .filter() 
@@ -108,6 +127,7 @@ The zoos are concerned about animals with a lower population count. Using filter
 
 */
 const lowPopulationAnimals = [];
+lowPopulationAnimals.push(zooAnimals.filter(population => population.population < 5))
 console.log(lowPopulationAnimals);
 
 /* Request 4: .reduce() 
@@ -115,7 +135,9 @@ console.log(lowPopulationAnimals);
 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;
+const populationTotal = zooAnimals.reduce((a,b)=>{
+  return a+=b.population;
+}, 0);
 console.log(populationTotal);
 
 
diff --git a/challenges/prototypes.js b/challenges/prototypes.js
index 4cafc33e95..d56a82d398 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.length = length,
+  this.width = width,
+  this.height = height;
+}
 
 
-/* == 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
+/* == 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 volume = this.length * this.width * this.height;
+}
 
 
 /* == 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)
+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 surfaceArea = 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.   
+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.   
 */
+let 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