diff --git a/.DS_Store b/.DS_Store
new file mode 100644
index 000000000..efe573ea2
Binary files /dev/null and b/.DS_Store differ
diff --git a/00_hello/hello.rb b/00_hello/hello.rb
new file mode 100644
index 000000000..97176ed02
--- /dev/null
+++ b/00_hello/hello.rb
@@ -0,0 +1,6 @@
+def hello
+	"Hello!"
+end
+def greet(who)
+	"Hello, #{who}!"
+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..a083e4356
--- /dev/null
+++ b/01_temperature/temperature.rb
@@ -0,0 +1,15 @@
+def ftoc(temp)
+	temp = temp.to_f
+	temp -= 32
+	temp *= 5
+	temp /= 9
+	temp
+end
+
+def ctof (temp)
+	temp = temp.to_f
+	temp *= 9
+	temp /= 5
+	temp += 32
+	temp
+end
diff --git a/02_calculator/calculator.rb b/02_calculator/calculator.rb
new file mode 100644
index 000000000..d5957ab4f
--- /dev/null
+++ b/02_calculator/calculator.rb
@@ -0,0 +1,31 @@
+def add(x, y)
+	x + y
+end
+
+def subtract(x, y)
+	x - y
+end
+
+def sum(array)
+	if array.length == 0
+		0
+	else
+		array.inject{|result, n| result + n}
+	end
+end
+
+def multiply(array)
+	array.inject{|result, n| result * n}
+end
+
+def power(x, y)
+	x ** y
+end
+
+def factorial(number)
+	if number == 0
+		return 1
+	else
+		(1..number).inject{|result, n| result * n}
+	end
+end
\ No newline at end of file
diff --git a/02_calculator/calculator_spec.rb b/02_calculator/calculator_spec.rb
index fef7e9d00..a2dd1a8e2 100644
--- a/02_calculator/calculator_spec.rb
+++ b/02_calculator/calculator_spec.rb
@@ -79,21 +79,38 @@
 
 describe "#multiply" do
 
-  it "multiplies two numbers"
-
-  it "multiplies several numbers"
-  
+  it "multiplies two numbers" do
+    expect(multiply([3,7])).to eq(21)
+  end
+  it "multiplies several numbers" do
+    expect(multiply([3,7,2])).to eq(42)
+  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
+  it "returns 1 if exponent is 0" do
+    expect(power(1,0)).to eq(1)
+  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..83e25ab0f
--- /dev/null
+++ b/03_simon_says/simon_says.rb
@@ -0,0 +1,38 @@
+def echo(string)
+	string
+end
+
+def shout(string)
+	string.upcase
+end
+
+def repeat(string, n = 2)
+	new_string = (string + " ") * n
+	new_string.strip!
+end
+
+def start_of_word(string, n)
+	letters = string.split ''
+	letters[0..(n-1)].join ''
+end
+
+def first_word(string)
+	words = string.split ' '
+	words[0]
+end
+
+def titleize(string)
+	words = string.split ' '
+	little_words = ["and", "the", "over"]
+	if little_words.include? words[0]
+		words[0][0] = words[0][0].upcase
+	end
+	words.each do |word|
+		if little_words.include? word
+			next
+		else
+			word[0] = word[0].upcase
+		end
+	end
+	words.join ' '
+end
\ No newline at end of file
diff --git a/04_pig_latin/pig_latin.rb b/04_pig_latin/pig_latin.rb
new file mode 100644
index 000000000..81024ebbd
--- /dev/null
+++ b/04_pig_latin/pig_latin.rb
@@ -0,0 +1,21 @@
+def translate(string)
+	translation = ''
+	vowels = ["a", "e", "i", "o", "u"]
+	words = string.split ' '
+	words.each do |word|
+		letters = word.split ''
+		until vowels.include? letters[0]
+			letter = letters.shift
+			letters.push letter
+		end
+		#if next letter is q, checks end of word for u and shifts it if necessary
+		if letters[0] == "u" && letters[-1] == "q"
+			letter = letters.shift
+			letters.push letter
+		end
+		letters.push "ay"
+		translation += (letters.join '') + ' '
+	end
+	translation.strip!
+end
+translate("quiet")
\ No newline at end of file
diff --git a/05_silly_blocks/silly_blocks.rb b/05_silly_blocks/silly_blocks.rb
new file mode 100644
index 000000000..1b9997337
--- /dev/null
+++ b/05_silly_blocks/silly_blocks.rb
@@ -0,0 +1,16 @@
+def reverser
+	words = yield.split ' '
+	words.each do |word|
+		word.reverse!
+	end
+	words.join ' '
+end
+
+def adder(add=1)
+  yield + add
+end
+
+def repeater(repeat=1)
+	repeat.times do yield
+	end
+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..c0d753eca
--- /dev/null
+++ b/06_performance_monitor/performance_monitor.rb
@@ -0,0 +1,7 @@
+def measure(n=1)
+	start = Time.now
+	n.times do
+		yield
+	end
+	(Time.now - start) / 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..4a9b76961
--- /dev/null
+++ b/07_hello_friend/friend.rb
@@ -0,0 +1,9 @@
+class Friend
+	def greeting(name = nil)
+		if name == nil
+			"Hello!"
+		else
+			"Hello, #{name}!"
+		end
+	end
+end
\ No newline at end of file
diff --git a/08_book_titles/.DS_Store b/08_book_titles/.DS_Store
new file mode 100644
index 000000000..070ec7597
Binary files /dev/null and b/08_book_titles/.DS_Store differ
diff --git a/08_book_titles/book.rb b/08_book_titles/book.rb
new file mode 100644
index 000000000..ff6bcd6e8
--- /dev/null
+++ b/08_book_titles/book.rb
@@ -0,0 +1,19 @@
+class Book
+	attr_accessor :title
+
+	def title
+		words = @title.split ' '
+		articles = ["the", "a", "an", "and", "in", "of"]
+		if articles.include? words[0]
+			words[0][0] = words[0][0].upcase
+		end
+		words.each do |word|
+			if articles.include? word
+				next
+			else
+				word[0] = word[0].upcase
+			end
+		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..bd1d054ec
--- /dev/null
+++ b/09_timer/timer.rb
@@ -0,0 +1,35 @@
+class Timer
+	attr_accessor :seconds
+
+	def initialize
+		@seconds = 0
+	end
+
+	def time_string
+		"#{padded(hours)}:#{padded(minutes)}:#{padded(seconds)}"
+	end
+
+	def hours
+		hours = @seconds / 3600
+	end
+
+	def minutes
+		minutes = (@seconds - hours * 3600) / 60
+	end
+
+	def seconds
+		seconds = @seconds % 60
+	end
+
+	def padded(number)
+		number = number.to_s
+		digits = number.length
+		if digits == 0
+			"00"
+		elsif digits == 1
+			"0" + number
+		else
+			number
+		end
+	end
+end
\ No newline at end of file
diff --git a/09_timer/timer_spec.rb b/09_timer/timer_spec.rb
index 40b33f23f..39bcca573 100644
--- a/09_timer/timer_spec.rb
+++ b/09_timer/timer_spec.rb
@@ -45,16 +45,17 @@
   # 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/.DS_Store b/10_temperature_object/.DS_Store
new file mode 100644
index 000000000..1aa1a5e99
Binary files /dev/null and b/10_temperature_object/.DS_Store differ
diff --git a/10_temperature_object/temperature.rb b/10_temperature_object/temperature.rb
new file mode 100644
index 000000000..6ae229cdb
--- /dev/null
+++ b/10_temperature_object/temperature.rb
@@ -0,0 +1,42 @@
+class Temperature
+	#converts options hash into C° and F° values
+	def initialize(options = {})
+		@degreesf, @degreesc = options[:f], options[:c]
+
+		if @degreesf != nil && @degreesc == nil
+			@degreesc = (@degreesf - 32) * 5.0 / 9.0
+		elsif @degreesc != nil && @degreesf == nil
+			@degreesf = (@degreesc * 9.0 / 5.0) + 32
+		end
+	end
+	#returns converted input as F°
+	def in_fahrenheit
+		@degreesf
+	end
+	#returns converted input as C°
+	def in_celsius
+		@degreesc
+	end
+	#Factory method for inputs from C°
+	def self.from_celsius(temperature)
+		Temperature.new(:c => temperature)
+	end
+	#Factory method for inputs from F°
+	def self.from_fahrenheit(temperature)
+		Temperature.new(:f => temperature)
+	end
+end
+#Temperature subclass to convert input to C°
+class Celsius < Temperature
+	def initialize(temperature)
+		@degreesc = temperature
+		@degreesf = (temperature * 9.0 / 5.0) + 32
+	end
+end
+#Temperature subclass to convert input to F°
+class Fahrenheit < Temperature
+	def initialize(temperature)
+		@degreesf = temperature
+		@degreesc = (temperature - 32) * 5.0 / 9.0
+	end
+end
\ No newline at end of file
diff --git a/11_dictionary/dictionary.rb b/11_dictionary/dictionary.rb
new file mode 100644
index 000000000..0da3d60a7
--- /dev/null
+++ b/11_dictionary/dictionary.rb
@@ -0,0 +1,51 @@
+class Dictionary
+	attr_accessor :entries
+
+	#creates empty hash for entries
+	def initialize
+		@entries = {}
+	end
+
+	#adds entries with key and value(if given)
+	def add(input)
+		if input.class == String
+			@entries[input] = nil
+		else
+			@entries.merge!(input)
+		end
+	end
+
+	#returns keys alphabetically
+	def keywords
+		@entries.keys.sort
+	end
+
+	#checks whether or not a given key is in @entries
+	def include?(word)
+		if @entries.keys.include?(word)
+			true
+		else
+			false
+		end
+	end
+
+	#finds keys and parts of keys and returns all relevant entries
+	def find(search)
+		results = {}
+		@entries.each do |key, value|
+			if key.start_with? search
+				results[key] = value
+			end
+		end
+		results
+	end
+
+	#sorts and prints @entries in [key] "value" format
+	def printable
+		printed = @entries.sort.map do |key,value|
+			"[#{key}] \"#{value}\""
+		end
+		printed.join "\n"
+	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..e79db13ed
--- /dev/null
+++ b/12_rpn_calculator/rpn_calculator.rb
@@ -0,0 +1,88 @@
+class RPNCalculator
+	attr_accessor :calculator
+	#sets array for operands awaiting operations
+	def initialize
+		@operands = []
+	end
+	#adds operands to array
+	def push(n)
+		@operands.push n
+	end
+	#returns total of operations
+	def value
+		@operands[-1]
+	end
+	#adds operands when possible, otherwise raises error
+	def plus
+		if @operands.size>= 2
+			@operands.push (@operands.pop + @operands.pop)
+		else
+			raise "calculator is empty"
+		end
+	end
+	#subtracts operands when possible, otherwise raises error
+	def minus
+		if @operands.size>= 2
+			new_n = (@operands[-2] - @operands[-1])
+			@operands.pop(2)
+			@operands.push new_n
+		else
+			raise "calculator is empty"
+		end
+	end
+	#divides operands when possible, otherwise raises error
+	def divide
+		if @operands.size>= 2
+			new_n = (@operands[-2].to_f / @operands[-1].to_f)
+			@operands.pop(2)
+			@operands.push new_n
+		else
+			raise "calculator is empty"
+		end
+	end
+	#multiplies operands when possible, otherwise raises error
+	def times
+		if @operands.size>= 2
+			new_n = (@operands[-2] * @operands[-1])
+			@operands.pop(2)
+			@operands.push new_n
+		else
+			raise "calculator is empty"
+		end
+	end
+	#evaluates a string and turns components into operators or operands
+	def tokens(string)
+		operators = ["+", "-", "*", "/"]
+		inputs = string.split ' '
+		tokenized = inputs.collect do |input|
+			if operators.include? input
+				input.to_sym
+			else
+				input.to_i
+			end
+		end
+		tokenized
+	end
+	#evaluats tokenized string
+	def evaluate(string)
+		tokens(string).each do |input|
+			if input == :+
+				self.plus
+			elsif input == :-
+				self.minus
+			elsif input == :/
+				self.divide
+			elsif input == :*
+				self.times
+			else
+				self.push input
+			end
+		end
+		self.value
+	end
+
+end
+
+
+
+
diff --git a/14_array_extensions/array_extensions.rb b/14_array_extensions/array_extensions.rb
new file mode 100644
index 000000000..f0b1711d2
--- /dev/null
+++ b/14_array_extensions/array_extensions.rb
@@ -0,0 +1,13 @@
+class Array
+	def sum
+		self.inject(0){|sum,x| sum + x}
+	end
+
+	def square
+		self.map {|x| x * x}
+	end
+
+	def square!
+		self.map! {|x| x * x}
+	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..ef5560e2f
--- /dev/null
+++ b/15_in_words/in_words.rb
@@ -0,0 +1,81 @@
+class Fixnum
+	def in_words(number = 0)
+	  number = self
+	  if number == 0
+	    return 'zero'
+	  end
+
+	  number_phrase = ''
+	  ones = ['one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine']
+	  tens = ['ten', 'twenty', 'thirty', 'forty', 'fifty', 'sixty', 'seventy', 'eighty', 'ninety']
+	  teens = ['eleven', 'twelve', 'thirteen', 'fourteen', 'fifteen', 'sixteen', 'seventeen', 'eighteen', 'nineteen']
+	  left_over = number
+
+	  calculating = left_over / 1000000000000
+	  left_over = left_over - calculating * 1000000000000
+	  if calculating > 0
+	    trillions = calculating.in_words
+	    number_phrase = number_phrase + trillions + ' trillion'
+	    if left_over > 0
+	      number_phrase = number_phrase + ' '
+	    end
+	  end
+	  calculating = left_over / 1000000000
+	  left_over = left_over - calculating * 1000000000
+	  if calculating > 0
+	    billions = calculating.in_words
+	    number_phrase = number_phrase + billions + ' billion'
+	    if left_over > 0
+	      number_phrase = number_phrase + ' '
+	    end
+	  end
+	  calculating = left_over / 1000000
+	  left_over = left_over - calculating * 1000000
+	  if calculating > 0
+	    millions = calculating.in_words
+	    number_phrase = number_phrase + millions + ' million'
+	    if left_over > 0
+	      number_phrase = number_phrase + ' '
+	    end
+	  end
+	  calculating = left_over / 1000
+	  left_over  = left_over - calculating * 1000
+	  if calculating > 0
+	    thousands = calculating.in_words
+	    number_phrase = number_phrase + thousands + ' thousand'
+	    if left_over > 0
+	      number_phrase = number_phrase + ' '
+	    end
+	  end
+	  calculating = left_over / 100
+	  left_over  = left_over - calculating * 100
+	  if calculating > 0
+	    hundreds  = calculating.in_words
+	    number_phrase = number_phrase + hundreds + ' hundred'
+	    if left_over > 0
+	      number_phrase = number_phrase + ' '
+	    end
+	  end
+	  calculating = left_over / 10
+	  left_over  = left_over - calculating * 10
+	  if calculating > 0
+	    if ((calculating == 1) and (left_over > 0))
+	      number_phrase = number_phrase + teens[left_over-1]
+	      left_over = 0
+	    else
+	      number_phrase = number_phrase + tens[calculating-1]
+	    end
+
+	    if left_over > 0
+	      number_phrase = number_phrase + ' '
+	    end
+	  end
+	  calculating = left_over
+	  left_over  = 0
+
+	  if calculating > 0
+	    number_phrase = number_phrase + ones[calculating-1]
+	  end
+	  number_phrase
+	end
+end
\ No newline at end of file