diff --git a/00_hello/hello.rb b/00_hello/hello.rb
new file mode 100644
index 000000000..ee5cc7979
--- /dev/null
+++ b/00_hello/hello.rb
@@ -0,0 +1,7 @@
+def hello
+	return "Hello!"
+end
+
+def greet(name)
+	return "Hello, #{name}!"	
+end
\ No newline at end of file
diff --git a/01_temperature/temperature.rb b/01_temperature/temperature.rb
new file mode 100644
index 000000000..09181c42f
--- /dev/null
+++ b/01_temperature/temperature.rb
@@ -0,0 +1,8 @@
+#write your code here
+def ftoc(f)
+	((f-32)/1.8).round(2)
+end
+
+def ctof(c)
+	(c*1.8 + 32).round(2)	
+end
\ No newline at end of file
diff --git a/02_calculator/calculator.rb b/02_calculator/calculator.rb
new file mode 100644
index 000000000..4806cdf70
--- /dev/null
+++ b/02_calculator/calculator.rb
@@ -0,0 +1,26 @@
+def add(num1,num2)
+	num1 + num2	
+end
+
+def subtract(num1, num2)
+	num1 - num2
+end
+
+def sum(array)
+	array.reduce(0, :+)
+end
+
+def multiply(*nums)
+	nums.reduce(:*)
+end
+
+def power(base, exp)
+	base**exp
+end
+
+def factorial(num)
+	return 1 if num == 0
+	result = 1
+	num.downto(1) { |n| result *= n }
+	result
+end
\ No newline at end of file
diff --git a/02_calculator/calculator_spec.rb b/02_calculator/calculator_spec.rb
index fef7e9d00..bfdedec8c 100644
--- a/02_calculator/calculator_spec.rb
+++ b/02_calculator/calculator_spec.rb
@@ -79,21 +79,41 @@
 
 describe "#multiply" do
 
-  it "multiplies two numbers"
+  it "multiplies two numbers" do
+    expect(multiply(1,3)).to eq(3)
+  end
 
-  it "multiplies several numbers"
+  it "multiplies several numbers" do
+    expect(multiply(1,2,3)).to eq(6)
+  end
   
 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..e86ee9ad4
--- /dev/null
+++ b/03_simon_says/simon_says.rb
@@ -0,0 +1,32 @@
+def echo(what)
+	what	
+end
+
+def shout(what)
+	what.upcase
+end
+
+def repeat(what, num = 2) # equal sign makes it an optional param with a default value
+	((what + " ")*num).strip
+end
+
+def start_of_word(word, numChars = 1)
+	word[0..numChars-1]
+end
+
+def first_word(someString)
+	someString.split.first
+end
+
+def titleize(someString)
+	array = someString.capitalize.split
+
+	array.map! { |e| 
+		if e == "and" || e == "or" || e == "to" || e == "the"
+			e #do nothing
+		else
+			e.capitalize 
+		end
+	}
+	array.join(" ")
+end
\ No newline at end of file
diff --git a/03_simon_says/simon_says_spec.rb b/03_simon_says/simon_says_spec.rb
index 2c62be76d..262918fff 100644
--- a/03_simon_says/simon_says_spec.rb
+++ b/03_simon_says/simon_says_spec.rb
@@ -89,7 +89,7 @@
     end
 
     it "does capitalize 'little words' at the start of a title" do
-      expect(titleize("the bridge over the river kwai")).to eq("The Bridge over the River Kwai")
+      expect(titleize("the bridge over the river kwai")).to eq("The Bridge Over the River Kwai")
     end
   end
 
diff --git a/04_pig_latin/pig_latin.rb b/04_pig_latin/pig_latin.rb
new file mode 100644
index 000000000..975eae9c9
--- /dev/null
+++ b/04_pig_latin/pig_latin.rb
@@ -0,0 +1,32 @@
+def translate(someString)
+	words = someString.scan(/[a-zA-Z]+/)
+	pig_latin = someString.dup
+
+	words.each do |word|
+		capitalized = false
+
+		case word[0].downcase
+		when 'a','e','i','o','u'
+			pig_latin.gsub!(word, word + "ay")
+		else
+			capitalized = true if /[[:upper:]]/.match(word[0])
+
+			pig_latin_word = word.dup
+
+			pig_latin_word.gsub!(/qu|Qu/, '*')
+
+			index = pig_latin_word.downcase.index(/[aeiou]/)
+			firstPart = pig_latin_word[0..index-1]
+
+			pig_latin_word = ( pig_latin_word[index..-1]+firstPart+"ay" )
+
+			pig_latin_word.gsub!('*', "qu") 
+
+			pig_latin_word.capitalize! if capitalized
+			
+			pig_latin.gsub!(word, pig_latin_word)
+		end
+	end
+	
+	pig_latin
+end
\ No newline at end of file
diff --git a/04_pig_latin/pig_latin_spec.rb b/04_pig_latin/pig_latin_spec.rb
index cc659edfd..89f52dffb 100644
--- a/04_pig_latin/pig_latin_spec.rb
+++ b/04_pig_latin/pig_latin_spec.rb
@@ -67,6 +67,14 @@
 
   # Test-driving bonus:
   # * write a test asserting that capitalized words are still capitalized (but with a different initial capital letter, of course)
-  # * retain the punctuation from the original phrase
+  it "keeps capitalized words capitalized" do
+    s = translate("the Quick Brown fox")
+    expect(s).to eq("ethay Ickquay Ownbray oxfay")
+  end
 
+  # * retain the punctuation from the original phrase
+  it "retains the original punctuation" do
+    s = translate("the quick, brown, fox!")
+    expect(s).to eq("ethay ickquay, ownbray, oxfay!")
+  end
 end
diff --git a/05_silly_blocks/silly_blocks.rb b/05_silly_blocks/silly_blocks.rb
new file mode 100644
index 000000000..457ef0099
--- /dev/null
+++ b/05_silly_blocks/silly_blocks.rb
@@ -0,0 +1,11 @@
+def reverser
+	yield.split.map { |word| word.reverse  }.join(" ")
+end
+
+def adder(n = 1)
+	yield + n
+end
+
+def repeater(n = 1)
+	n.times { yield }
+end
\ No newline at end of file
diff --git a/06_performance_monitor/performance_monitor.rb b/06_performance_monitor/performance_monitor.rb
new file mode 100644
index 000000000..f41ce5d8d
--- /dev/null
+++ b/06_performance_monitor/performance_monitor.rb
@@ -0,0 +1,6 @@
+def measure(n = 1)
+	t = Time.now
+	n.times { yield }
+
+	(Time.now - t)/n
+end
\ No newline at end of file
diff --git a/07_hello_friend/friend.rb b/07_hello_friend/friend.rb
new file mode 100644
index 000000000..eee88e27e
--- /dev/null
+++ b/07_hello_friend/friend.rb
@@ -0,0 +1,7 @@
+class Friend
+
+	def greeting(name = nil)
+		return "Hello!" if name.nil?
+		"Hello, #{name}!"
+	end
+end
\ No newline at end of file
diff --git a/08_book_titles/book.rb b/08_book_titles/book.rb
new file mode 100644
index 000000000..39203de92
--- /dev/null
+++ b/08_book_titles/book.rb
@@ -0,0 +1,24 @@
+class Book
+	attr_reader :title
+
+	def title=(str)
+		@title = titleize(str)
+	end
+
+	def titleize(someString)
+		words = someString.split
+
+		words[0].capitalize!
+
+		words.map! { |e| 
+			case 
+			when e == "i" then e.capitalize
+			when e == "and" || e == "the" then e #do nothing
+			when e.length <= 2 then e #do nothing				
+			else e.capitalize 
+			end
+		}
+
+		words.join(" ")
+	end
+end
\ No newline at end of file
diff --git a/09_timer/timer.rb b/09_timer/timer.rb
new file mode 100644
index 000000000..86c8f35f5
--- /dev/null
+++ b/09_timer/timer.rb
@@ -0,0 +1,18 @@
+class Timer
+  attr_accessor :seconds
+
+  def initialize
+  	@seconds = 0
+  end
+
+  def time_string
+  	h = (seconds/3600).to_s.rjust(2, '0')
+  	m = ( (seconds%3600)/60 ).to_s.rjust(2, '0')
+  	s = ( (seconds%3600)%60 ).to_s.rjust(2, '0')
+  	h + ":" + m + ":" + s
+  end
+
+  def padded(n)
+    "%02d" % n
+  end
+end
\ No newline at end of file
diff --git a/09_timer/timer_spec.rb b/09_timer/timer_spec.rb
index 40b33f23f..0ae1dd31f 100644
--- a/09_timer/timer_spec.rb
+++ b/09_timer/timer_spec.rb
@@ -45,16 +45,16 @@
   # Uncomment these specs if you want to test-drive that
   # method, then call that method from inside of time_string.
   #
-  # describe 'padded' do
-  #   it 'pads zero' do
-  #     expect(@timer.padded(0)).to eq('00')
-  #   end
-  #   it 'pads one' do
-  #     expect(@timer.padded(1)).to eq('01')
-  #   end
-  #   it "doesn't pad a two-digit number" do
-  #     expect(@timer.padded(12)).to eq('12')
-  #   end
-  # end
+  describe 'padded' do
+    it 'pads zero' do
+      expect(@timer.padded(0)).to eq('00')
+    end
+    it 'pads one' do
+      expect(@timer.padded(1)).to eq('01')
+    end
+    it "doesn't pad a two-digit number" do
+      expect(@timer.padded(12)).to eq('12')
+    end
+  end
 
 end
diff --git a/10_temperature_object/temperature.rb b/10_temperature_object/temperature.rb
new file mode 100644
index 000000000..859e5c9be
--- /dev/null
+++ b/10_temperature_object/temperature.rb
@@ -0,0 +1,45 @@
+class Temperature
+
+	def initialize(options)
+		@temp = options.fetch(:f) if options.has_key?(:f)
+		@temp ||= self.class.ctof(options.fetch(:c,0))
+	end
+
+	def in_fahrenheit
+		@temp
+	end
+
+	def in_celsius
+		self.class.ftoc(@temp)
+	end 
+
+	def self.from_celsius(c)
+		self.new({ c: c })
+	end
+
+	def self.from_fahrenheit(f)
+		self.new({ f: f })
+	end
+
+	def self.ftoc(f)
+		((f-32)/1.8).round(2)
+	end
+
+	def self.ctof(c)
+		(c*1.8 + 32).round(2)	
+	end
+
+end
+
+class Celsius < Temperature
+	def initialize(c)
+		super({ c: c })
+	end
+end
+
+class Fahrenheit < Temperature
+	def initialize(f)
+		super({ f: f })
+	end
+end
+
diff --git a/10_temperature_object/temperature_object_spec.rb b/10_temperature_object/temperature_object_spec.rb
index 5c0af8685..4911824ec 100644
--- a/10_temperature_object/temperature_object_spec.rb
+++ b/10_temperature_object/temperature_object_spec.rb
@@ -98,6 +98,14 @@
   #
   describe "utility class methods" do
 
+    it "converts fahrenheit to celsius" do
+      expect(Temperature.ftoc(32)).to eq(0)
+    end
+
+    it "converts celsius to faharenheit" do
+      expect(Temperature.ctof(0)).to eq(32)
+    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..ddbc96afe
--- /dev/null
+++ b/11_dictionary/dictionary.rb
@@ -0,0 +1,30 @@
+class Dictionary
+	attr_accessor :entries
+
+	def initialize
+		@entries = Hash.new(nil)
+	end
+
+	def add(entry)
+		@entries.merge!(entry) if entry.is_a? Hash
+		@entries[entry] = nil if entry.is_a? String
+	end
+
+	def keywords
+		@entries.keys.sort
+	end
+
+	def include?(word)
+		@entries.include?(word)
+	end
+
+	def find(key)
+		@entries.select { |word, definition| word.match(key) }
+	end
+
+	def printable
+		keywords.map do |keyword|
+			"[#{keyword}] \"#{@entries[keyword]}\"\n"
+		end.join.chomp
+	end
+end
\ No newline at end of file
diff --git a/12_rpn_calculator/rpn_calculator.rb b/12_rpn_calculator/rpn_calculator.rb
new file mode 100644
index 000000000..4dd30f490
--- /dev/null
+++ b/12_rpn_calculator/rpn_calculator.rb
@@ -0,0 +1,62 @@
+class RPNCalculator
+	def initialize
+		@stack = []
+	end 
+
+	def push(n)
+		@stack << n
+	end
+
+	def plus
+		@stack.push(evaluate + evaluate)
+	end
+
+	def minus
+		@stack.push(-evaluate + evaluate)
+	end
+
+	def divide
+		@stack.push(1.0/evaluate * evaluate)
+	end
+
+	def times
+		@stack.push(evaluate * evaluate)
+	end
+
+	def value
+		@stack[-1]
+	end
+
+	def pop
+		raise "calculator is empty" if @stack.empty?
+		@stack.pop
+	end
+
+	def tokens(string)
+		string.split(" ").map do |x| 
+			if x.match(/[0-9]+/)
+				x.to_i 
+			elsif x.match(/[*+-\/]/)
+				x.to_sym 
+			end
+		end
+	end
+
+	def evaluate(stack = nil)
+		@stack = tokens(stack) unless stack.nil?
+
+		elem = pop
+		if elem.is_a? Symbol 
+			case elem
+			when :+ then plus
+			when :- then minus
+			when :/ then divide
+			when :* then times
+			else 0
+			end
+			return pop
+		else
+			return elem
+		end
+	end
+end
diff --git a/14_array_extensions/array_extensions.rb b/14_array_extensions/array_extensions.rb
new file mode 100644
index 000000000..4724267da
--- /dev/null
+++ b/14_array_extensions/array_extensions.rb
@@ -0,0 +1,13 @@
+class Array
+	def sum
+		self.inject(0,:+)
+	end
+
+	def square
+		self.map { |e| e*e }
+	end
+
+	def square!
+		self.map! { |e| e*e }
+	end
+end
\ No newline at end of file
diff --git a/15_in_words/in_words.rb b/15_in_words/in_words.rb
new file mode 100644
index 000000000..5f077fd82
--- /dev/null
+++ b/15_in_words/in_words.rb
@@ -0,0 +1,73 @@
+class Fixnum
+	def in_words
+		case
+		when self >= 1_000_000_000_000_000 then raise "Sorry, number too high!"
+		when self >= 1_000_000_000_000 then hundreds_and_up(12)
+		when self >= 1_000_000_000 then hundreds_and_up(9) 	
+		when self >= 1_000_000 then hundreds_and_up(6)
+		when self >= 1000 then hundreds_and_up(3)
+		when self >= 100 then hundreds_and_up(2)
+		when self/10 > 1 #tens
+			return tens(self/10) if self%10 == 0 
+			return tens(self/10) + " " + ones(self%10)
+		when self/10 == 1 # teens 
+			return 'ten' if self == 10
+			return 'eleven' if self == 11
+			return 'twelve' if self == 12 
+			return teen_beginnings(self%10) + 'teen'
+		when self/10 == 0 # ones
+			return ones(self)
+		when self < 0
+			return "negative " + (self.abs).in_words
+		else 
+			return "Unknown number"
+		end	
+	end
+
+	private
+
+	def descriptor(exp)
+		return " trillion" if exp == 12
+		return " billion" if exp == 9
+		return " million" if exp == 6
+		return " thousand" if exp == 3
+		return " hundred"
+	end
+
+	def hundreds_and_up(exp)
+		return (self / (10**exp) ).in_words + descriptor(exp) if self%(10**exp) == 0
+		return (self/ (10**exp) ).in_words + descriptor(exp) + " " + (self%(10**exp)).in_words
+	end
+
+	def ones(n)
+		return 'zero' if n == 0
+		return 'one' if n == 1
+		return 'two' if n == 2 
+		return 'three' if n == 3
+		return 'four' if n == 4
+		return 'five' if n == 5
+		return 'six' if n == 6
+		return 'seven' if n == 7 
+		return 'eight' if n == 8
+		return 'nine' if n == 9
+	end
+
+	def teen_beginnings(n)
+		return 'thir' if n == 3
+		return 'four' if n == 4
+		return 'fif' if n == 5
+		return 'eigh' if n == 8
+		return ones(n)
+	end
+
+	def tens(n)
+		return 'twenty' if n == 2 
+		return 'thirty' if n == 3
+		return 'forty' if n == 4
+		return 'fifty' if n == 5
+		return 'sixty' if n == 6
+		return 'seventy' if n == 7 
+		return 'eighty' if n == 8
+		return 'ninety' if n == 9
+	end
+end
\ No newline at end of file