diff --git a/src/arrays.js b/src/arrays.js
index f24d6ef..3b372ee 100644
--- a/src/arrays.js
+++ b/src/arrays.js
@@ -6,33 +6,87 @@ const each = (elements, cb) => {
   // Iterates over a list of elements, yielding each in turn to the `cb` function.
   // This only needs to work with arrays.
   // based off http://underscorejs.org/#each
+  if (Array.isArray(elements)) {
+    for (let i = 0; i < elements.length; i++) {
+      cb(elements[i], i);
+    }
+  } else {
+    throw new Error();
+  }
+  elements.forEach((item, index) => {
+    cb(item, index);
+  });
 };
 
 const map = (elements, cb) => {
   // Produces a new array of values by mapping each value in list through a transformation function (iteratee).
   // Return the new array.
+  const myArray = [];
+  each(elements, (element, index) => {
+    myArray.push(cb(element, index));
+  });
+  // const myArray = elements.map((item, index) => {
+  // return cb(item, index);
+  // });
+
+  return myArray;
 };
 
 const reduce = (elements, cb, memo) => {
   // Combine all elements into a single value going from left to right.
   // Elements will be passed one by one into `cb`.
   // `memo` is the starting value.  If `memo` is undefined then make `elements[0]` the initial value.
+
+  // let sum;
+  // if (memo === undefined) sum = elements[0];
+  // memo.reduce((sum, elements) => {
+  //   return cb(elements);
+  // });
+
+  // if (memo === undefined) {
+  //   memo = elements[0];
+  // }
+  // for (let i = 0; i < memo.length; i++) {
+  //   memo.push.cb(elements);
+  // }
+  if (!memo) {
+    memo = elements.shift();
+  }
+  for (let i = 0; i < elements.length; i++) {
+    memo = cb(memo, elements[i]);
+  }
+  return memo;
 };
 
 const find = (elements, cb) => {
   // Look through each value in `elements` and pass each element to `cb`.
   // If `cb` returns `true` then return that element.
   // Return `undefined` if no elements pass the truth test.
+
+  for (let i = 0; i < elements.length; i++) if (cb(elements[i]) === true) return elements[i];
+  return 'undefined';
 };
 
 const filter = (elements, cb) => {
   // Similar to `find` but you will return an array of all elements that passed the truth test
   // Return an empty array if no elements pass the truth test
-};
 
+  const arr = [];
+  for (let i = 0; i < elements.length; i++) {
+    if (cb(elements[i]) === true) arr.push(elements[i]);
+  }
+  return arr;
+};
+// flatten rearranges a nested array
 const flatten = (elements) => {
   // Flattens a nested array (the nesting can be to any depth).
   // Example: flatten([1, [2], [3, [[4]]]]); => [1, 2, 3, 4];
+  let arr = [];
+  for (let i = 0; i < elements.length; i++) {
+    if (Array.isArray(elements[i])) {
+      arr = arr.concat(flatten(elements[i]));
+    } else arr.push(elements[i]);
+  } return arr;
 };
 
 /* eslint-enable no-unused-vars, max-len */
diff --git a/src/class.js b/src/class.js
index 8276e29..414acd1 100644
--- a/src/class.js
+++ b/src/class.js
@@ -5,9 +5,20 @@
 // Add a method called `comparePasswords`.  `comparePasswords` should have a parameter
 // for a potential password that will be compared to the `password` property.
 // Return true if the potential password matches the `password` property.  Otherwise return false.
+class User {
+  constructor(options) {
+    this.email = options.email;
+    this.password = options.password;
+  }
 
+  comparePasswords(myPassword) {
+    if (this.password === myPassword) return true;
+    return false;
+  }
+}
 
-/* eslint-disable no-undef */ // Remove this comment once you write your classes.
+
+ // Remove this comment once you write your classes.
 
 
 // Create a class called `Animal` and a class called `Cat`.
@@ -19,6 +30,27 @@
 // `meow` that should return the string `<name> meowed!` where `<name>` is the `name`
 // property set on the Cat instance.
 
+class Animal {
+  constructor(options) {
+    this.age = options.age;
+  }
+
+  growOlder() {
+    return this.age += 1;
+  }
+}
+
+class Cat extends Animal {
+  constructor(options) {
+    super(options);
+    this.name = options.name;
+  }
+
+  meow() {
+    return `${this.name} meowed!`;
+  }
+}
+
 
 module.exports = {
   User,
diff --git a/src/closure.js b/src/closure.js
index 4c98af0..0c8b0ed 100644
--- a/src/closure.js
+++ b/src/closure.js
@@ -5,17 +5,35 @@ const counter = () => {
   // Example: const newCounter = counter();
   // newCounter(); // 1
   // newCounter(); // 2
+  let count = 0;
+  return () => ++count;
 };
 
 const counterFactory = () => {
   // Return an object that has two methods called `increment` and `decrement`.
   // `increment` should increment a counter variable in closure scope and return it.
   // `decrement` should decrement the counter variable and return it.
+  let count = 0;
+
+  return {
+    increment: () => {
+      return ++count;
+    },
+    decrement: () => {
+      return --count;
+    }
+  };
 };
 
 const limitFunctionCallCount = (cb, n) => {
   // Should return a function that invokes `cb`.
   // The returned function should only allow `cb` to be invoked `n` times.
+  let count = 0;
+  return (x) => {
+    count++;
+    if (n >= count) return cb(x);
+    return null;
+  };
 };
 
 const cacheFunction = (cb) => {
@@ -25,6 +43,8 @@ const cacheFunction = (cb) => {
   // If the returned function is invoked with arguments that it has already seen
   // then it should return the cached result and not invoke `cb` again.
   // `cb` should only ever be invoked once for a given set of arguments.
+
+  const cache = {};
 };
 
 /* eslint-enable no-unused-vars */
diff --git a/src/es6.js b/src/es6.js
index eb846ab..9fbba36 100644
--- a/src/es6.js
+++ b/src/es6.js
@@ -7,50 +7,53 @@
 //----------------
 // const, =>, default parameters, arrow functions default return statements using ()
 
-var food = 'pineapple';
+let food = 'pineapple'; // false
 
-var isMyFavoriteFood = function(food) {
+const isMyFavoriteFood = (food) => { 
   food = food || 'thousand-year-old egg'; //This sets a default value if `food` is falsey
   return food === 'thousand-year-old egg';
 };
 
-var isThisMyFavorite = isMyFavoriteFood(food);
+let isThisMyFavorite = isMyFavoriteFood(food);
 
 //----------------
 //const, class, template literals, enhanced object literals (foo: foo, -> foo,)
 
-var User = function(options) {
+
+class User { 
+  constructor(options) {
   this.username = options.username;
   this.password = options.password;
-  this.sayHi = function() {
-    return this.username + ' says hello!';
-  };
 }
+  sayHi() {
+    return `${this.username} says hello!`;
+  }; 
+} 
 
-var username = 'JavaScriptForever';
-var password = 'password';
+let username = 'JavaScriptForever';
+let password = 'password';
 
-var me = new User({
-  username: username,
-  password: password,
+const me = new User({
+  username,
+  password
 });
 
 // ----------------
 // let, const, =>, ... (spread operator)
 
-var addArgs = function () {
-  var sum = 0;
-  for (var i = 0; i < arguments.length; i++) {
+const addArgs = () => {
+  let sum = 0;
+  for (let i = 0; i < arguments.length; i++) {
     sum += arguments[i];
   }
   return sum;
 };
 
-var argsToCb = function (cb) {
-  var args = Array.prototype.slice.call(arguments);
-  return cb.apply(null, args.splice(1));
+const argsToCb = (cb) => {
+  let args = Array.prototype.slice.call(arguments);
+  return cb(...args);
 };
 
-var result = argsToCb(addArgs, 1, 2, 3, 4, 5); //result should be 15
+let result = argsToCb(addArgs, 1, 2, 3, 4, 5); //result should be 15
 
 /* eslint-enable */
diff --git a/src/index.html b/src/index.html
new file mode 100644
index 0000000..e69de29
diff --git a/src/objects.js b/src/objects.js
index ba39c6c..c307338 100644
--- a/src/objects.js
+++ b/src/objects.js
@@ -1,21 +1,50 @@
 // Complete the following underscore functions.
 // Reference http://underscorejs.org/ for examples.
+// Object.keys(obj).forEach((key) => {});
+// const testObj = {
+//   name: 'steve',
+//   age: 12,
+//   food: 'pizza'
+// };
 
 const keys = (obj) => {
   // Retrieve all the names of the object's properties.
   // Return the keys as strings in an array.
   // Based on http://underscorejs.org/#keys
+  const keysString = [];
+  Object.keys(obj).forEach((key) => {
+    keysString.push(key);
+  });
+  return keysString;
 };
 
+// console.log(keys(testObj));
+
 const values = (obj) => {
   // Return all of the values of the object's own properties.
   // Ignore functions
   // http://underscorejs.org/#values
+  // QUESTION: return Object.keys(obj).forEach(obj[keys]);
+  const keysString = [];
+  Object.keys(obj).forEach((key) => {
+    keysString.push(obj[key]);
+  });
+  return keysString;
 };
 
 const mapObject = (obj, cb) => {
   // Like map for arrays, but for objects. Transform the value of each property in turn.
   // http://underscorejs.org/#mapObject
+  // Loop over the elements and call them back
+  // to the callback then return the elements in a new array.
+  // const newArr = obj.forEach(cb() => {
+  //   cb(obj);
+  // });
+  // return
+  // const arrKeys = keys(obj);
+  // const arrValues = values(obj);
+  // for (let i = 0; i < arrValues.length; i++) {
+  // }
 };
 
 const pairs = (obj) => {
diff --git a/src/recursion.js b/src/recursion.js
index a3e997e..307f886 100644
--- a/src/recursion.js
+++ b/src/recursion.js
@@ -3,16 +3,22 @@
 const nFibonacci = (n) => {
   // fibonacci sequence: 1 2 3 5 8 13 ...
   // return the nth number in the sequence
+  if (n <= 1) return 1;
+  return nFibonacci(n - 1) + nFibonacci(n - 2);
 };
 
 const nFactorial = (n) => {
   // factorial example: !5 = 5 * 4 * 3 * 2 * 1
   // return the factorial of `n`
+  if (n < 2) return 1;
+  return n * (nFactorial(n - 1));
 };
-
+// checkMatchingLeaves is very similar to 'contains' method in the tree data structure.
 const checkMatchingLeaves = (obj) => {
   // return true if every property on `obj` is the same
   // otherwise return false
+
+
 };
 
 /* eslint-enable no-unused-vars */
diff --git a/src/scripts.js b/src/scripts.js
new file mode 100644
index 0000000..e69de29
diff --git a/src/styles.css b/src/styles.css
new file mode 100644
index 0000000..e69de29
diff --git a/src/this.js b/src/this.js
index 8ea3020..4d32e00 100644
--- a/src/this.js
+++ b/src/this.js
@@ -5,10 +5,18 @@
 class User {
   constructor(options) {
     // set a username and password property on the user object that is created
+    this.username = options.username,
+    this.password = options.password
   }
   // create a method on the User class called `checkPassword`
   // this method should take in a string and compare it to the object's password property
   // return `true` if they match, otherwise return `false`
+
+  checkPassword(string) {
+    if (string === this.password) {
+      return true;
+    } return false;
+  } 
 }
 
 const me = new User({ username: 'LambdaSchool', password: 'correcthorsebatterystaple' });
@@ -19,6 +27,9 @@ const checkPassword = function comparePasswords(passwordToCompare) {
   // use `this` to access the object's `password` property.
   // do not modify this function's parameters
   // note that we use the `function` keyword and not `=>`
+  if (passwordToCompare == this.password) {
+    return true;
+  } return false;
 };
 
 // invoke `checkPassword` on `me` by explicitly setting the `this` context