diff --git a/00_hello/hello.rb b/00_hello/hello.rb
new file mode 100644
index 000000000..61626e810
--- /dev/null
+++ b/00_hello/hello.rb
@@ -0,0 +1,7 @@
+def hello
+  "Hello!"
+end
+
+def greet(name)
+  "Hello, #{name}!"
+end
diff --git a/01_temperature/temperature.rb b/01_temperature/temperature.rb
new file mode 100644
index 000000000..160742143
--- /dev/null
+++ b/01_temperature/temperature.rb
@@ -0,0 +1,7 @@
+def ftoc(f)
+  (f.to_f - 32.0) * 5.0/9.0
+end
+
+def ctof(c)
+  c.to_f * 9.0/5.0 + 32
+end
diff --git a/02_calculator/calculator.rb b/02_calculator/calculator.rb
new file mode 100644
index 000000000..bb5cea694
--- /dev/null
+++ b/02_calculator/calculator.rb
@@ -0,0 +1,24 @@
+def add(first, second)
+  first + second
+end
+
+def subtract(first, second)
+  first - second
+end
+
+def sum(array)
+  array.reduce(0) { |a, b| a + b }
+end
+
+def multiply(array)
+  array.reduce { |a, b| a * b }
+end
+
+def power(base, factor)
+  base ** factor
+end
+
+def factorial(n)
+  return 1 if n == 0
+  (1..n).to_a.reduce { |a, b| a * b }
+end
diff --git a/02_calculator/calculator_spec.rb b/02_calculator/calculator_spec.rb
index fef7e9d00..31d5b2838 100644
--- a/02_calculator/calculator_spec.rb
+++ b/02_calculator/calculator_spec.rb
@@ -79,21 +79,37 @@
 
 describe "#multiply" do
 
-  it "multiplies two numbers"
+  it "multiplies two numbers" do
+    expect(multiply([2,3])).to eq(6)
+  end
+
+  it "multiplies several numbers" do
+    expect(multiply([2,3,4])).to eq(24)
+  end
 
-  it "multiplies several numbers"
-  
 end
 
 describe "#power" do
-  it "raises one number to the power of another number"
+  it "raises one number to the power of another number" do
+    expect(power(2,3)).to eq(8)
+  end
 end
 
 # http://en.wikipedia.org/wiki/Factorial
 describe "#factorial" do
-  it "computes the factorial of 0"
-  it "computes the factorial of 1"
-  it "computes the factorial of 2"
-  it "computes the factorial of 5"
-  it "computes the factorial of 10"
+  it "computes the factorial of 0" do
+    expect(factorial(0)).to eq(1)
+  end
+  it "computes the factorial of 1" do
+    expect(factorial(1)).to eq(1)
+  end
+  it "computes the factorial of 2" do
+    expect(factorial(2)).to eq(2)
+  end
+  it "computes the factorial of 5" do
+    expect(factorial(5)).to eq(120)
+  end
+  it "computes the factorial of 10" do
+    expect(factorial(10)).to eq(3628800)
+  end
 end
diff --git a/03_simon_says/simon_says.rb b/03_simon_says/simon_says.rb
new file mode 100644
index 000000000..5b4ffebc7
--- /dev/null
+++ b/03_simon_says/simon_says.rb
@@ -0,0 +1,40 @@
+def echo(text)
+  text
+end
+
+def shout(text)
+  text.upcase
+end
+
+def repeat(text, times=2)
+  text + ((" "+text) * (times-1))
+end
+
+def start_of_word(text, letters)
+  text[0..letters-1]
+end
+
+def first_word(text)
+  array = text.split(' ')
+  array[0]
+end
+
+def capitalize(word)
+  word[0] = word[0].upcase
+  word
+end
+
+def titleize(text)
+  array = text.split(' ')
+  little_words = ['a', 'an', 'the', 'and', 'or', 'but', 'for', 'by', 'near', 'under', 'over', 'of']
+  output = array.map.with_index(0) do |word, index|
+    if index == 0
+      capitalize(word)
+    elsif little_words.include?(word)
+      word
+    else
+      capitalize(word)
+    end
+  end
+  output = output.join(' ')
+end
diff --git a/04_pig_latin/pig_latin.rb b/04_pig_latin/pig_latin.rb
new file mode 100644
index 000000000..f9138c700
--- /dev/null
+++ b/04_pig_latin/pig_latin.rb
@@ -0,0 +1,28 @@
+def translate_word(text)
+  vowels = ['a', 'e', 'i', 'o', 'u', 'y']
+  if vowels.include?(text[0])
+    output = text + 'ay'
+  else
+    array = text.split('')
+    array.length.times do
+      current_letter = array.shift
+      if vowels.include?(current_letter)
+        array.unshift(current_letter)
+        break
+      elsif current_letter == 'q'
+        current_letter = current_letter + array.shift
+        array.push(current_letter)
+      else
+        array.push(current_letter)
+      end
+    end
+    output = array.join('') + 'ay'
+  end
+  output
+end
+
+def translate(text)
+  words = text.split(' ')
+  output = words.map { |word| translate_word(word) }
+  output.join(' ')
+end
diff --git a/05_silly_blocks/silly_blocks.rb b/05_silly_blocks/silly_blocks.rb
new file mode 100644
index 000000000..b2ae784ad
--- /dev/null
+++ b/05_silly_blocks/silly_blocks.rb
@@ -0,0 +1,22 @@
+def word_reverser
+  input = yield.split('')
+  output = []
+  while input.length > 0
+    output.push(input.pop)
+  end
+  output.join('')
+end
+
+def reverser
+  words = yield.split(' ')
+  output = words.map { |word| word_reverser { word } }
+  output.join(' ')
+end
+
+def adder(addend=1)
+  yield + addend
+end
+
+def repeater(multiplicand=1)
+  multiplicand.times { yield }
+end
diff --git a/06_performance_monitor/performance_monitor.rb b/06_performance_monitor/performance_monitor.rb
new file mode 100644
index 000000000..57f3b7600
--- /dev/null
+++ b/06_performance_monitor/performance_monitor.rb
@@ -0,0 +1,11 @@
+def measure(count=1)
+  recorded_times = []
+  count.times do
+    start = Time.now
+    yield
+    finish = Time.now
+    recorded_times.push(finish - start)
+  end
+  sum_of_times = recorded_times.reduce(0){|sum, x| sum + x}
+  sum_of_times / count
+end
diff --git a/07_hello_friend/friend.rb b/07_hello_friend/friend.rb
new file mode 100644
index 000000000..5b2147a57
--- /dev/null
+++ b/07_hello_friend/friend.rb
@@ -0,0 +1,9 @@
+class Friend
+  def greeting(name="")
+    if name.length == 0
+      "Hello!"
+    else
+      "Hello, #{name}!"
+    end
+  end
+end
diff --git a/08_book_titles/book.rb b/08_book_titles/book.rb
new file mode 100644
index 000000000..dd3e6dca3
--- /dev/null
+++ b/08_book_titles/book.rb
@@ -0,0 +1,29 @@
+class Book
+  def title=(title)
+    @title = titleize(title)
+  end
+  def title
+    @title
+  end
+
+  def capitalize(word)
+    word[0] = word[0].upcase
+    word
+  end
+
+  def titleize(text)
+    array = text.split(' ')
+    little_words = ['a', 'an', 'the', 'and', 'or', 'but', 'for', 'by', 'near', 'under', 'over', 'of', 'in']
+    output = array.map.with_index(0) do |word, index|
+      if index == 0
+        capitalize(word)
+      elsif little_words.include?(word)
+        word
+      else
+        capitalize(word)
+      end
+    end
+    output = output.join(' ')
+  end
+
+end
diff --git a/09_timer/timer.rb b/09_timer/timer.rb
new file mode 100644
index 000000000..b847c46a5
--- /dev/null
+++ b/09_timer/timer.rb
@@ -0,0 +1,21 @@
+class Timer
+  def initialize
+    @seconds = 0
+  end
+  def seconds=(seconds=0)
+    @seconds = seconds
+  end
+  def seconds
+    @seconds
+  end
+  def time_string
+    minutes = @seconds / 60
+    seconds = @seconds % 60
+    hours = minutes / 60
+    minutes = minutes % 60
+    "#{format_time_division(hours)}:#{format_time_division(minutes)}:#{format_time_division(seconds)}"
+  end
+  def format_time_division(number)
+    number.to_s.rjust(2, '0')
+  end
+end
diff --git a/10_temperature_object/temperature.rb b/10_temperature_object/temperature.rb
new file mode 100644
index 000000000..528d0cbef
--- /dev/null
+++ b/10_temperature_object/temperature.rb
@@ -0,0 +1,35 @@
+class Temperature
+  def initialize(options={})
+    @f = options[:f] ||= options[:fahrenheit]
+    @c = options[:c] ||= options[:celsius]
+  end
+  def self.ftoc(f)
+    (f.to_f - 32.0) * 5.0/9.0
+  end
+  def self.ctof(c)
+    c.to_f * 9.0/5.0 + 32
+  end
+  def in_fahrenheit
+    @f || self.class.ctof(@c)
+  end
+  def in_celsius
+    @c || self.class.ftoc(@f)
+  end
+  def self.from_celsius(c)
+    Temperature.new({:c => c})
+  end
+  def self.from_fahrenheit(f)
+    Temperature.new({:f => f})
+  end
+end
+
+class Celsius < Temperature
+  def initialize(c)
+    @c = c
+  end
+end
+class Fahrenheit < Temperature
+  def initialize(f)
+    @f = f
+  end
+end
diff --git a/10_temperature_object/temperature_object_spec.rb b/10_temperature_object/temperature_object_spec.rb
index 5c0af8685..98802560b 100644
--- a/10_temperature_object/temperature_object_spec.rb
+++ b/10_temperature_object/temperature_object_spec.rb
@@ -97,7 +97,12 @@
   # run *all* the tests during your refactoring, to make sure you did it right
   #
   describe "utility class methods" do
-
+    it "ftoc method" do
+      expect(Temperature.ftoc(32)).to eq(0.0)
+    end
+    it "ctof method" do
+      expect(Temperature.ftoc(212)).to eq(100.0)
+    end
   end
 
   # Here's another way to solve the problem!
diff --git a/11_dictionary/dictionary.rb b/11_dictionary/dictionary.rb
new file mode 100644
index 000000000..f7a952390
--- /dev/null
+++ b/11_dictionary/dictionary.rb
@@ -0,0 +1,37 @@
+class Dictionary
+  def initialize
+    @dict = {}
+    @keywords = []
+  end
+  def entries
+    @dict
+  end
+  def add(pair)
+    if pair.class == Hash
+      @dict.merge!(pair)
+      @keywords.push(pair.keys[0])
+    elsif
+      @dict.merge!(pair => nil)
+      @keywords.push(pair)
+    end
+  end
+  def keywords
+    @keywords.sort
+  end
+  def include?(query)
+    @keywords.include?(query)
+  end
+  def find(query)
+    @dict.select { |key, value| key.start_with? query}
+  end
+  def printable
+    @keywords.sort!
+    output = ""
+    @keywords.each do |keyword|
+      output += "[#{keyword}] \"#{@dict[keyword]}\"\n"
+    end
+    output = output.slice(0, output.length-1) # remove trailing \n
+  end
+end
+
+# ""
diff --git a/12_rpn_calculator/rpn_calculator.rb b/12_rpn_calculator/rpn_calculator.rb
new file mode 100644
index 000000000..d203c2887
--- /dev/null
+++ b/12_rpn_calculator/rpn_calculator.rb
@@ -0,0 +1,33 @@
+class RPNCalculator
+  def initialize
+    @stack = []
+  end
+  def push(n)
+    @stack.push(n.to_f)
+  end
+  def value
+    @stack[-1]
+  end
+  def operation
+    begin
+      a = @stack.pop
+      b = @stack.pop
+      yield(a,b)
+    rescue
+      raise Exception, "calculator is empty"
+    end
+  end
+  def plus
+    operation { |a,b| @stack.push(a + b) }
+  end
+  def minus
+    operation { |a,b| @stack.push(b - a) }
+  end
+  def times
+    operation { |a,b| @stack.push(a * b) }
+  end
+  def divide
+    operation { |a,b| @stack.push(b / a) }
+  end
+
+end
diff --git a/13_xml_document/index.html b/13_xml_document/index.html
deleted file mode 100644
index 900ff72d5..000000000
--- a/13_xml_document/index.html
+++ /dev/null
@@ -1,123 +0,0 @@
-<html>
-  <head>
-    <title>Test-First Teaching: learn_ruby: xml_document</title>
-    <link href="../assets/style.css" media="screen" rel="stylesheet" type="text/css" />
-  </head>
-  <body>
-    <div class="header">
-      <h1><a href="http://testfirst.org">TestFirst.org</a></h1>
-      <h2>the home of test-first teaching</h2>
-    </div>
-    <div class="nav">
-      <h2><a href="../index.html">learn_ruby</a></h2>
-      <b>Labs:</b>
-      <ul>
-        <li><a href="../00_hello/index.html">00 Hello</a></li>
-        <li><a href="../01_temperature/index.html">01 Temperature</a></li>
-        <li><a href="../02_calculator/index.html">02 Calculator</a></li>
-        <li><a href="../03_simon_says/index.html">03 Simon Says</a></li>
-        <li><a href="../04_pig_latin/index.html">04 Pig Latin</a></li>
-        <li><a href="../05_silly_blocks/index.html">05 Silly Blocks</a></li>
-        <li><a href="../06_performance_monitor/index.html">06 Performance Monitor</a></li>
-        <li><a href="../07_hello_friend/index.html">07 Hello Friend</a></li>
-        <li><a href="../08_book_titles/index.html">08 Book Titles</a></li>
-        <li><a href="../09_timer/index.html">09 Timer</a></li>
-        <li><a href="../10_temperature_object/index.html">10 Temperature Object</a></li>
-        <li><a href="../11_dictionary/index.html">11 Dictionary</a></li>
-        <li><a href="../12_rpn_calculator/index.html">12 Rpn Calculator</a></li>
-        <li>13 Xml Document</li>
-        <li><a href="../14_array_extensions/index.html">14 Array Extensions</a></li>
-        <li><a href="../15_in_words/index.html">15 In Words</a></li>
-      </ul>
-    </div>
-    <h1>xml_document</h1>
-    <div class="content"><div class="rspec_file">  <div class="intro"><h1>Topics</h1>
-
-<ul>
-<li>method_missing</li>
-<li>blocks</li>
-<li>strings</li>
-<li>hashes</li>
-</ul>
-
-
-<h1>Builder</h1>
-
-<p>Here we will implement the so-called Builder Pattern: we will make an object, XmlDocument, that <em>builds</em> an XML file, which can contain arbitrary tags.</p>
-</div>
-  <div class="tests">
-    <h1>Tests</h1>
-<a class="raw_file" href="xml_document_spec.rb">xml_document_spec.rb</a>
-    <pre>
-# Stuff you'll learn:
-# method_missing
-# nested closures
-# &quot;builder pattern&quot;
-
-require &quot;xml_document&quot;
-
-describe XmlDocument do
-  before do
-    @xml = XmlDocument.new
-  end
-
-  it &quot;renders an empty tag&quot; do
-    expect(@xml.hello).to eq(&quot;&lt;hello/&gt;&quot;)
-  end
-
-  it &quot;renders a tag with attributes&quot; do
-    expect(@xml.hello(:name =&gt; 'dolly')).to eq(&quot;&lt;hello name='dolly'/&gt;&quot;)
-  end
-
-  it &quot;renders a randomly named tag&quot; do
-    tag_name = (1..8).map{|i| ('a'..'z').to_a[rand(26)]}.join
-    expect(@xml.send(tag_name)).to eq(&quot;&lt;#{tag_name}/&gt;&quot;)
-  end
-
-  it &quot;renders block with text inside&quot; do
-    expect(@xml.hello do
-      &quot;dolly&quot;
-    end).to eq(&quot;&lt;hello&gt;dolly&lt;/hello&gt;&quot;)
-  end
-
-  it &quot;nests one level&quot; do
-    expect(@xml.hello do
-      @xml.goodbye
-    end).to eq(&quot;&lt;hello&gt;&lt;goodbye/&gt;&lt;/hello&gt;&quot;)
-  end
-
-  it &quot;nests several levels&quot; do
-    xml = XmlDocument.new
-    expect(xml.hello do
-      xml.goodbye do
-        xml.come_back do
-          xml.ok_fine(:be =&gt; &quot;that_way&quot;)
-        end
-      end
-    end).to eq(&quot;&lt;hello&gt;&lt;goodbye&gt;&lt;come_back&gt;&lt;ok_fine be='that_way'/&gt;&lt;/come_back&gt;&lt;/goodbye&gt;&lt;/hello&gt;&quot;)
-  end
-
-  it &quot;indents&quot; do
-    @xml = XmlDocument.new(true)
-    expect(@xml.hello do
-      @xml.goodbye do
-        @xml.come_back do
-          @xml.ok_fine(:be =&gt; &quot;that_way&quot;)
-        end
-      end
-    end).to eq(
-    &quot;&lt;hello&gt;\n&quot; +
-    &quot;  &lt;goodbye&gt;\n&quot; +
-    &quot;    &lt;come_back&gt;\n&quot; +
-    &quot;      &lt;ok_fine be='that_way'/&gt;\n&quot; +
-    &quot;    &lt;/come_back&gt;\n&quot; +
-    &quot;  &lt;/goodbye&gt;\n&quot; +
-    &quot;&lt;/hello&gt;\n&quot;)
-  end
-end</pre>
-  </div>
-</div>
-</div>
-    <div class="footer"><a href="http://testfirst.org">TestFirst.org</a></div>
-  </body>
-</html>
diff --git a/13_xml_document/xml_document_spec.rb b/13_xml_document/xml_document_spec.rb
deleted file mode 100644
index fa1995818..000000000
--- a/13_xml_document/xml_document_spec.rb
+++ /dev/null
@@ -1,77 +0,0 @@
-# # Topics
-#
-# * method_missing
-# * blocks
-# * strings
-# * hashes
-#
-# # Builder
-#
-# Here we will implement the so-called Builder Pattern: we will make an object, XmlDocument, that *builds* an XML file, which can contain arbitrary tags.
-
-# Stuff you'll learn:
-# method_missing
-# nested closures
-# "builder pattern"
-
-require "xml_document"
-
-describe XmlDocument do
-  before do
-    @xml = XmlDocument.new
-  end
-
-  it "renders an empty tag" do
-    expect(@xml.hello).to eq("<hello/>")
-  end
-
-  it "renders a tag with attributes" do
-    expect(@xml.hello(:name => 'dolly')).to eq("<hello name='dolly'/>")
-  end
-
-  it "renders a randomly named tag" do
-    tag_name = (1..8).map{|i| ('a'..'z').to_a[rand(26)]}.join
-    expect(@xml.send(tag_name)).to eq("<#{tag_name}/>")
-  end
-
-  it "renders block with text inside" do
-    expect(@xml.hello do
-      "dolly"
-    end).to eq("<hello>dolly</hello>")
-  end
-
-  it "nests one level" do
-    expect(@xml.hello do
-      @xml.goodbye
-    end).to eq("<hello><goodbye/></hello>")
-  end
-
-  it "nests several levels" do
-    xml = XmlDocument.new
-    expect(xml.hello do
-      xml.goodbye do
-        xml.come_back do
-          xml.ok_fine(:be => "that_way")
-        end
-      end
-    end).to eq("<hello><goodbye><come_back><ok_fine be='that_way'/></come_back></goodbye></hello>")
-  end
-
-  it "indents" do
-    @xml = XmlDocument.new(true)
-    expect(@xml.hello do
-      @xml.goodbye do
-        @xml.come_back do
-          @xml.ok_fine(:be => "that_way")
-        end
-      end
-    end).to eq(
-    "<hello>\n" +
-    "  <goodbye>\n" +
-    "    <come_back>\n" +
-    "      <ok_fine be='that_way'/>\n" +
-    "    </come_back>\n" +
-    "  </goodbye>\n" +
-    "</hello>\n")
-  end
-end
diff --git a/14_array_extensions/array_extensions.rb b/14_array_extensions/array_extensions.rb
new file mode 100644
index 000000000..1c30761ed
--- /dev/null
+++ b/14_array_extensions/array_extensions.rb
@@ -0,0 +1,11 @@
+class Array
+  def sum
+    self.reduce(0) { |a, b| a + b }
+  end
+  def square
+    self.map { |item| item * item }
+  end
+  def square!
+    self.map! { |item| item * item }
+  end
+end
diff --git a/15_in_words/in_words.rb b/15_in_words/in_words.rb
new file mode 100644
index 000000000..326b39bb3
--- /dev/null
+++ b/15_in_words/in_words.rb
@@ -0,0 +1,76 @@
+require 'pry'
+require 'pry-byebug'
+
+class Fixnum
+  def in_words
+    string = self.to_s
+    one_less_digit = string[1..string.length].to_i
+    first_digit = string[0].to_i
+    output = ""
+    orders_of_magnitude = {
+      1000000000000 => "trillion",
+      1000000000 => "billion",
+      1000000 => "million",
+      1000 => "thousand",
+      100 => "hundred",
+    }
+    orders_of_magnitude.each do |magnitude, word|
+      if self >= magnitude
+        quantity = self / magnitude
+        remainder = self - quantity * magnitude
+        if remainder > 0
+          output += quantity.in_words + ' ' + word + ' ' + remainder.in_words
+        else
+          output += quantity.in_words + ' ' + word
+        end
+        return output
+      end
+    end
+    dictionary = {
+      90 => "ninety",
+      80 => "eighty",
+      70 => "seventy",
+      60 => "sixty",
+      50 => "fifty",
+      40 => "forty",
+      30 => "thirty",
+      20 => "twenty",
+      19 => "nineteen",
+      18 => "eighteen",
+      17 => "seventeen",
+      16 => "sixteen",
+      15 => "fifteen",
+      14 => "fourteen",
+      13 => "thirteen",
+      12 => "twelve",
+      11 => "eleven",
+      10 => "ten",
+      9 => "nine",
+      8 => "eight",
+      7 => "seven",
+      6 => "six",
+      5 => "five",
+      4 => "four",
+      3 => "three",
+      2 => "two",
+      1 => "one"
+    }
+    dictionary.each do |match, word|
+      if self/match > 0 && self > 20
+        if one_less_digit == 0
+          output += word
+        else
+          output += word + ' ' + one_less_digit.in_words
+        end
+        output.strip!
+        break
+      elsif self == match
+        output = word
+        output.strip!
+      elsif self/10 == 0 && self == 0
+        output = "zero"
+      end
+    end
+    output
+  end
+end