diff --git a/package.json b/package.json
index d887b5c..8bdf711 100644
--- a/package.json
+++ b/package.json
@@ -27,6 +27,8 @@
   },
   "dependencies": {
     "babel-preset-es2015": "^6.24.0",
-    "eslint-config-airbnb": "^14.1.0"
+    "eslint-config-airbnb": "^14.1.0",
+    "eslint-plugin-jsx-a11y": "^3.0.2",
+    "eslint-plugin-react": "^6.10.3"
   }
 }
diff --git a/src/project-1.js b/src/project-1.js
index dc26cfb..0bbe312 100644
--- a/src/project-1.js
+++ b/src/project-1.js
@@ -3,115 +3,154 @@
 const multiplyByTen = (num) => {
   // return num after multiplying it by ten
   // code here
+  return num * 10;
 };
 
 const subtractFive = (num) => {
   // return num after subtracting five
   // code here
+  return num - 5;
 };
 
 const areSameLength = (str1, str2) => {
   // return true if the two strings have the same length
   // otherwise return false
   // code here
+  if (str1.length === str2.length) {
+    return true;
+  }
+  return false;
 };
 
 const areEqual = (x, y) => {
   // return true if x and y are the same
   // otherwise return false
   // code here
+  if (x === y) {
+    return true;
+  }
+  return false;
 };
 
 const lessThanNinety = (num) => {
   // return true if num is less than ninety
   // otherwise return false
   // code here
+  if (num < 90) {
+    return true;
+  }
+  return false;
 };
 
 const greaterThanFifty = (num) => {
   // return true if num is greater than fifty
   // otherwise return false
   // code here
+  if (num > 50) {
+    return true;
+  }
+  return false;
 };
 
 const add = (x, y) => {
   // add x and y together and return the value
   // code here
+  return x + y;
 };
 
 const subtract = (x, y) => {
   // subtract y from x and return the value
   // code here
+  return x - y;
 };
 
 const divide = (x, y) => {
   // divide x by y and return the value
   // code here
+  return x / y;
 };
 
 const multiply = (x, y) => {
   // multiply x by y and return the value
   // code here
+  return x * y;
 };
 
 const getRemainder = (x, y) => {
   // return the remainder from dividing x by y
   // code here
+  return x % y;
 };
 
 const isEven = (num) => {
   // return true if num is even
   // otherwise return false
   // code here
+  if (num % 2 === 0) {
+    return true;
+  }
+  return false;
 };
 
 const isOdd = (num) => {
   // return true if num is odd
   // otherwise return false
   // code here
+  if (num % 2 !== 0) {
+    return true;
+  }
+  return false;
 };
 
 const square = (num) => {
   // square num and return the new value
   // code here
+  return Math.pow(num, 2);
 };
 
 const cube = (num) => {
   // cube num and return the new value
   // code here
+  return Math.pow(num, 3);
 };
 
 const raiseToPower = (num, exponent) => {
   // raise num to whatever power is passed in as exponent
   // code here
+  return Math.pow(num, exponent);
 };
 
 const roundNumber = (num) => {
   // round num and return it
   // code here
+  return Math.round(num);
 };
 
 const roundUp = (num) => {
   // round num up and return it
   // code here
+  return Math.ceil(num);
 };
 
 const addExclamationPoint = (str) => {
   // add an exclamation point to the end of str and return the new string
   // 'hello world' -> 'hello world!'
   // code here
+  return `${str}!`;
 };
 
 const combineNames = (firstName, lastName) => {
   // return firstName and lastName combined as one string and separated by a space.
   // 'Lambda', 'School' -> 'Lambda School'
   // code here
+  return `${firstName} ${lastName}`;
 };
 
 const getGreeting = (name) => {
   // Take the name string and concatenate other strings onto it so it takes the following form:
   // 'Sam' -> 'Hello Sam!'
   // code here
+  return `Hello ${name}!`;
 };
 
 // If you can't remember these area formulas then head over to Google or look at the test code.
@@ -119,21 +158,25 @@ const getGreeting = (name) => {
 const getRectangleArea = (length, width) => {
   // return the area of the rectangle by using length and width
   // code here
+  return length * width;
 };
 
 const getTriangleArea = (base, height) => {
   // return the area of the triangle by using base and height
   // code here
+  return 0.5 * base * height;
 };
 
 const getCircleArea = (radius) => {
   // return the rounded area of the circle given the radius
   // code here
+  return Math.round((Math.PI * Math.pow(radius, 2)));
 };
 
 const getRectangularPrismVolume = (length, width, height) => {
   // return the volume of the 3D rectangular prism given the length, width, and height
   // code here
+  return length * width * height;
 };
 
 // Do not modify code below this line.
diff --git a/src/project-2.js b/src/project-2.js
index 5fe0047..aaaaa49 100644
--- a/src/project-2.js
+++ b/src/project-2.js
@@ -3,6 +3,7 @@
 const getBiggest = (x, y) => {
   // x and y are integers.  Return the larger integer
   // if they are the same return either one
+  return Math.max(x, y);
 };
 
 const greeting = (language) => {
@@ -11,15 +12,28 @@ const greeting = (language) => {
   // language: 'Spanish' -> 'Hola!'
   // language: 'Chinese' -> 'Ni Hao!'
   // if language is undefined return 'Hello!'
+  if (language === 'German') {
+    return 'Guten Tag!';
+  } else if (language === 'Spanish') {
+    return 'Hola!';
+  } else if (language === 'Chinese') {
+    return 'Ni Hao!';
+  } return 'Hello!';
 };
 
 const isTenOrFive = (num) => {
   // return true if num is 10 or 5
   // otherwise return false
+  if (num === 10 || num === 5) {
+    return true;
+  } return false;
 };
 
 const isInRange = (num) => {
   // return true if num is less than 50 and greater than 20
+  if (num < 50 && num > 20) {
+    return true;
+  } return false;
 };
 
 const isInteger = (num) => {
@@ -29,6 +43,9 @@ const isInteger = (num) => {
   // -10 -> true
   // otherwise return false
   // hint: you can solve this using Math.floor
+  if (num === Math.floor(num)) {
+    return true;
+  } return false;
 };
 
 const fizzBuzz = (num) => {
@@ -36,6 +53,13 @@ const fizzBuzz = (num) => {
   // if num is divisible by 5 return 'buzz'
   // if num is divisible by 3 & 5 return 'fizzbuzz'
   // otherwise return num
+  if (num % 15 === 0) {
+    return 'fizzbuzz';
+  } else if (num % 3 === 0) {
+    return 'fizz';
+  } else if (num % 5 === 0) {
+    return 'buzz';
+  } return num;
 };
 
 const isPrime = (num) => {
@@ -44,35 +68,50 @@ const isPrime = (num) => {
   // hint: a prime number is only evenly divisible by itself and 1
   // hint2: you can solve this using a for loop
   // note: 0 and 1 are NOT considered prime numbers
+  if (num === 0 || num === 1) {
+    return false;
+  } for (let i = 2; i < num; i++) {
+    if (num % i === 0) {
+      return false;
+    }
+  } return true;
 };
 
 const returnFirst = (arr) => {
   // return the first item from the array
+  return arr[0];
 };
 
 const returnLast = (arr) => {
   // return the last item of the array
+  return arr[arr.length - 1];
 };
 
 const getArrayLength = (arr) => {
   // return the length of the array
+  return arr.length;
 };
 
 const incrementByOne = (arr) => {
   // arr is an array of integers
   // increase each integer by one
   // return the array
+  return arr.map(integer => integer + 1);
 };
 
 const addItemToArray = (arr, item) => {
   // add the item to the end of the array
   // return the array
+  arr.push(item);
+  return arr;
 };
 
 const addItemToFront = (arr, item) => {
   // add the item to the front of the array
   // return the array
   // hint: use the array method .unshift
+  arr.unshift(item);
+  return arr;
 };
 
 const wordsToSentence = (words) => {
@@ -80,26 +119,43 @@ const wordsToSentence = (words) => {
   // return a string that is all of the words concatenated together
   // spaces need to be between each word
   // example: ['Hello', 'world!'] -> 'Hello world!'
+  let sentence = '';
+  for (let i = 0; i < words.length; i++) {
+    if (i < words.length - 1) {
+      sentence = `${sentence}${words[i]} `;
+    } else {
+      sentence = `${sentence}${words[i]}`;
+    }
+  } return sentence;
 };
 
 const contains = (arr, item) => {
   // check to see if item is inside of arr
   // return true if it is, otherwise return false
+  for (let i = 0; i < arr.length; i++) {
+    if (item === arr[i]) {
+      return true;
+    }
+  } return false;
 };
 
 const addNumbers = (numbers) => {
   // numbers is an array of integers.
   // add all of the integers and return the value
+  return numbers.reduce((prev, curr) => prev + curr);
 };
 
 const averageTestScore = (testScores) => {
   // testScores is an array.  Iterate over testScores and compute the average.
   // return the average
+  const total = testScores.reduce((a, b) => a + b);
+  return total / testScores.length;
 };
 
 const largestNumber = (numbers) => {
   // numbers is an array of integers
   // return the largest integer
+  return numbers.reduce((a, b) => Math.max(a, b));
 };
 
 // Do not modify code below this line.
diff --git a/src/project-3.js b/src/project-3.js
index 7ca1430..85d2961 100644
--- a/src/project-3.js
+++ b/src/project-3.js
@@ -5,61 +5,91 @@ const makeCat = (name, age) => {
   // add an age property to the object with the value set to the age argument
   // add a method called meow that returns the string 'Meow!'
   // return the object
+  const foo = {
+    name,
+    age,
+    meow() { return 'Meow!'; },
+  }; return foo;
 };
 
 const addProperty = (object, property) => {
   // add the property to the object with a value of null
   // return the object
   // note: the property name is NOT 'property'.  The name is the value of the argument called property (a string)
+  object[property] = null;
+  return object;
 };
 
 const invokeMethod = (object, method) => {
   // method is a string that contains the name of a method on the object
   // invoke this method
   // nothing needs to be returned
+  object[method]();
 };
 
 const multiplyMysteryNumberByFive = (mysteryNumberObject) => {
   // mysteryNumberObject has a property called mysteryNumber
   // multiply the mysteryNumber property by 5 and return the product
+  return mysteryNumberObject.mysteryNumber * 5;
 };
 
 const deleteProperty = (object, property) => {
   // remove the property from the object
   // return the object
+  delete object[property];
+  return object;
 };
 
 const newUser = (name, email, password) => {
   // create a new object with properties matching the arguments passed in.
   // return the new object
+  const bar = {
+    name,
+    email,
+    password,
+  };
+  return bar;
 };
 
 const hasEmail = (user) => {
   // return true if the user has a value for the property 'email'
   // otherwise return false
+  if (user.email) {
+    return true;
+  } return false;
 };
 
 const hasProperty = (object, property) => {
   // return true if the object has the value of the property argument
   // property is a string
   // otherwise return false
+  if (object[property]) {
+    return true;
+  } return false;
 };
 
 const verifyPassword = (user, password) => {
   // check to see if the provided password matches the password property on the user object
   // return true if they match
   // otherwise return false
+  if (user.password === password) {
+    return true;
+  } return false;
 };
 
 const updatePassword = (user, newPassword) => {
   // replace the existing password on the user object with the value of newPassword
   // return the object
+  user.password = newPassword;
+  return user;
 };
 
 const addFriend = (user, newFriend) => {
   // user has a property called friends that is an array
   // add newFriend to the end of the friends array
   // return the user object
+  user.friends.push(newFriend);
+  return user;
 };
 
 const setUsersToPremium = (users) => {
@@ -67,6 +97,9 @@ const setUsersToPremium = (users) => {
   // each user object has the property 'isPremium'
   // set each user's isPremium property to true
   // return the users array
+  for (let i = 0; i < users.length; i++) {
+    users[i].isPremium = true;
+  } return users;
 };
 
 const sumUserPostLikes = (user) => {
@@ -75,6 +108,10 @@ const sumUserPostLikes = (user) => {
   // each post object has an integer property called 'likes'
   // sum together the likes from all the post objects
   // return the sum
+  let totalLikes = 0;
+  for (let i = 0; i < user.posts.length; i++) {
+    totalLikes += user.posts[i].likes;
+  } return totalLikes;
 };
 
 const addCalculateDiscountPriceMethod = (storeItem) => {
@@ -84,9 +121,12 @@ const addCalculateDiscountPriceMethod = (storeItem) => {
   // example:
   // price -> 20
   // discountPercentage -> .2
-  // discountPrice = 20 - (20 * .2)
+  // discountPrice = 20 - (20 * .2){
   // Make sure you return storeItem after adding the method to it
   // hint: arrow functions don't bind a this
+  storeItem.calculateDiscountPrice = function () {
+    return this.price * (1 - this.discountPercentage);
+  }; return storeItem;
 };
 
 // Do not modify code below this line.
diff --git a/src/project-4.js b/src/project-4.js
index 3a3a186..83b68a6 100644
--- a/src/project-4.js
+++ b/src/project-4.js
@@ -1,31 +1,42 @@
 const getFirstItem = (collection, cb) => {
   // invoke the callback function and pass the first item from the collection in as an argument
+  cb(collection[0]);
 };
 
 const getLength = (collection, cb) => {
   // Write a function called getLength that passes the length of the array into the callback
+  return cb(collection.length);
 };
 
 const getLastItem = (collection, cb) => {
   // Write a function called getLastItem which passes the getLastItem item of the array into the callback
+  return cb(collection[collection.length - 1]);
 };
 
 const sumNums = (x, y, cb) => {
   // Write a function called sumNums that adds two numbers and passes the result to the callback
+  return cb(x + y);
 };
 
 const multiplyNums = (x, y, cb) => {
   // Write a function called multiplyNums that multiplies two numbers and passes the result to the callback
+  return cb(x * y);
 };
 
 const contains = (collection, item, cb) => {
   // Write a function called contains that checks if an item is present inside of the given array.
   // Pass true to the callback if it is, otherwise pass false
+  for (let i = 0; i < collection.length; i++) {
+    if (collection[i] === item) {
+      return cb(true);
+    }
+  } return cb(false);
 };
 
 const removeDuplicates = (collection, cb) => {
   // Write a function called removeDuplicates that removes all duplicate values from the given array.
   // Pass the array to the callback function.  Do not mutate the original array.
+  return cb(Array.from(new Set(collection)));
 };
 
 module.exports = {