diff --git a/chapter04.js b/chapter04.js
index 12f6ef0..42670d7 100644
--- a/chapter04.js
+++ b/chapter04.js
@@ -10,41 +10,129 @@
 // Problem 1: The sum of a range
 function range(start, end, step=1) {
   // Your code here
+  var numRange = [];
+  if(start <= end) {
+    
+    for(var i = start; i <= end; i+=step) {
+      numRange.push(i);
+    }
+  }
+  else {
+    for(var j = start; j >= end; j+=step){
+      numRange.push(j);
+    }
+  }
+  return numRange;
 }
 
 function sum(array) {
   // Your code here
+  var total = 0;
+  for(var i = 0; i < array.length; ++i) {
+    total += array[i];
+  }
+  return total;
 }
 
 // Problem 2: Reversing an Array
 function reverseArray(array) {
   // Your code here
+  var revArr = [];
+  for(var i = array.length - 1; i > -1; --i) {
+    revArr.push(array[i]);
+  }
+  return revArr;
 }
 
 function reverseArrayInPlace(array) {
   // Your code here
+  var temp = 0;
+  for(var i = 0; i < array.length / 2; ++i) {
+    temp = array[i];
+    array[i] = array[array.length - 1 - i];
+    array[array.length - 1 - i] = temp;
+  }
 }
 
 // Problem 3: A List
 function arrayToList(array) {
   // Your code here
+  var list = {};
+  var node = list;
+  if(array.length > 0) {
+    list = {
+      value: array[0],
+      rest: {}
+    };
+    node = list;
+  }
+
+  for(var i = 1; i < array.length; ++i) {
+    if(i != array.length - 1){
+      node.rest = {
+        value: array[i],
+        rest: {}
+      };
+    }
+    else {
+      node.rest = {
+        value: array[i],
+        rest: null
+      };
+    }
+    node = node.rest;
+  }
+
+  return list;
 }
 
 function listToArray(list) {
   // Your code here
+  var array = [];
+  
+  var ptr = list;
+  while(ptr != null) {
+    array.push(ptr.value);
+    ptr = ptr.rest;
+  }
+  return array;
 }
 
 function nth(list, position) {
   // Your code here
+  var ptr = list;
+  for(var i = 0; i < position; ++i) {
+    if(ptr.rest === null) {
+      return undefined;
+    }
+    else {
+      ptr = ptr.rest;
+    }
+  }
+  return ptr.value;
 }
 
 function prepend(element, list) {
   // Your code here
+  var newList = {
+    value: element,
+    rest: list
+  }
+  return newList;
 }
 
 // Problem 4: Deep comparison
 function deepEqual(obj1, obj2) {
   // Your code here
+  for(var prop in obj1) {
+    if(typeof obj1[prop] == 'object' && typeof obj2[prop] == 'object') {
+      deepEqual(obj1[prop], obj2[prop]);
+    }
+    else if(obj1[prop] != obj2[prop]) {
+      return false;
+    }
+  }
+  return true;
 }
 
 
diff --git a/chapter05.js b/chapter05.js
index d1372cb..4d31386 100644
--- a/chapter05.js
+++ b/chapter05.js
@@ -21,12 +21,25 @@ ancestry.forEach(function(person) {
 // Problem 1: Flattening
 function flatten(arrays) {
   // Your code here
+  return arrays.reduce(function(a, b) {
+  	return a.concat(b);
+  }, []);
 }
 
 // Problem 2: Mother-child age difference
 /* This must return the average age difference instead of printing it */
 function averageMomChildAgeDiff() {
   // Your code here
+  var count = sumAges = 0;
+  for(person in byName) {
+  	ancestry.forEach(function(bio) {
+  		if(person == bio.mother) {
+  			count++;
+  			sumAges += bio.born - byName[person].born;
+  		}
+  	});
+  }
+  return sumAges / count;
 }
 
 // Problem 3: Historical life expectancy
@@ -35,6 +48,20 @@ function averageMomChildAgeDiff() {
  */
 function averageAgeByCentury() {
   // Your code here
+  function assignCentury(person) {
+  	return Math.ceil(person.died / 100);
+  }
+
+// Each inner array represents a century
+  var avgAge = {16: [], 17: [], 18: [], 19: [], 20: [], 21: []};
+  ancestry.forEach(function(person) {
+  	avgAge[assignCentury(person)].push(person.died - person.born);
+  });
+
+  for(century in avgAge) {
+  	avgAge[century] = average(avgAge[century]);
+  }
+  return avgAge;
 }
 
 
diff --git a/chapter13.js b/chapter13.js
index ab99bc6..3b39a89 100644
--- a/chapter13.js
+++ b/chapter13.js
@@ -10,6 +10,29 @@
 // Problem 1: Build table
 function buildTable(data) {
   // Your code here
+  var table = document.createElement('table');
+  var headerRow = document.createElement('tr');
+  table.appendChild(headerRow);
+
+  var textNode, htmlNode, currRow, initial = 1;
+  data.forEach(function(element) {
+  	currRow = document.createElement('tr');
+  	table.appendChild(currRow);
+  	for(prop in element) {
+  		if(initial) {
+  			htmlNode = document.createElement('th');
+  			textNode = document.createTextNode(prop);
+  			htmlNode.appendChild(textNode);
+  			headerRow.appendChild(htmlNode);
+  		}
+  		htmlNode = document.createElement('td');
+  		textNode = document.createTextNode(element[prop]);
+  		htmlNode.appendChild(textNode);
+  		currRow.appendChild(htmlNode);
+  	}
+  	initial = 0;
+  });
+  return table;
 }