diff --git a/session1/challenge/1_arithmetic.rb b/session1/challenge/1_arithmetic.rb
index fbe40463..5df7d0fa 100644
--- a/session1/challenge/1_arithmetic.rb
+++ b/session1/challenge/1_arithmetic.rb
@@ -1,13 +1,16 @@
+
 # fill out the method below
 # then test to see if you did them correctly with
 #  $ rake 1:1
 
 # Given a number, return 20 less than, that number multiplied by 5
-# 
+#
 # arithmetic1(10)     # => 30
 # arithmeitc1(10.5)   # => 32.5
 # arithmeitc1(-6)     # => -50
 
 def arithmetic1(n)
-  # the code for this method goes in here
+  n * 5 - 20
 end
+
+arithmetic1(10)
diff --git a/session1/challenge/2_arithmetic.rb b/session1/challenge/2_arithmetic.rb
index 21445b42..864570a2 100644
--- a/session1/challenge/2_arithmetic.rb
+++ b/session1/challenge/2_arithmetic.rb
@@ -9,4 +9,9 @@
 # arithmetic2(-6, -7)  # => -3.5
 
 def arithmetic2(a, b)
+if a < b
+  return a/2.0
+else
+  return b/2.0
+end
 end
diff --git a/session1/challenge/3_simple_logic.rb b/session1/challenge/3_simple_logic.rb
index c5f23c1c..54265178 100644
--- a/session1/challenge/3_simple_logic.rb
+++ b/session1/challenge/3_simple_logic.rb
@@ -8,5 +8,9 @@
 # ten_twenty(6) # => 10
 
 def ten_twenty(n)
-  # your code goes here
+  if n.even?
+    return 10
+  elsif n.odd?
+    return 20
+  end
 end
diff --git a/session1/challenge/4_logic.rb b/session1/challenge/4_logic.rb
index 6cc87dbc..496909a6 100644
--- a/session1/challenge/4_logic.rb
+++ b/session1/challenge/4_logic.rb
@@ -1,6 +1,6 @@
 # A grad student at a local university thinks he has discovered a formula to
-# predict what kind of grades a person will get. He says if you own less than 
-# 10 books, you will get a "D". If you own 10 to 20 books, you will get a "C", 
+# predict what kind of grades a person will get. He says if you own less than
+# 10 books, you will get a "D". If you own 10 to 20 books, you will get a "C",
 # and if you own more than 20 books, you will get a "B".
 # He further hypothesizes that if you actually read your books, then you will
 # get a full letter grade higher in every case.
@@ -10,4 +10,17 @@
 # grade(15, true)   # => "B"
 
 def grade(num_books, reads_books)
-end
\ No newline at end of file
+  if num_books < 10 && !reads_books
+    return "D"
+  elseif num_books < 10 && reads_books
+  return "C"
+elseif num_books (10..20) && !reads_books
+return "C"
+elseif num_books (10..20) && reads_books
+return "B"
+elsif num_books > 20 && !reads_books
+  return "B"
+elsif num_books > 20 &&reads_books
+  return "A"
+end
+end
diff --git a/session1/challenge/5_string.rb b/session1/challenge/5_string.rb
index 7901fc58..cfa605f5 100644
--- a/session1/challenge/5_string.rb
+++ b/session1/challenge/5_string.rb
@@ -1,8 +1,9 @@
 # Given a string, replace every instance of sad to happy
-# 
+#
 # add_more_ruby("The clowns were sad.")         # => "The clowns were happy."
 # add_more_ruby("The sad dad said sad stuff.")  # => "The happy dad said happy stuff."
 # add_more_ruby("Sad times are ahead!")         # => "Happy times are ahead!"
 
 def add_more_ruby(string)
+  string.gsub("sad", "happy").gsub("Sad", "Happy")
 end
diff --git a/session1/challenge/6_string.rb b/session1/challenge/6_string.rb
index 0fc38d0f..e6d7af64 100644
--- a/session1/challenge/6_string.rb
+++ b/session1/challenge/6_string.rb
@@ -1,11 +1,12 @@
 # You'll get a string and a boolean.
 # When the boolean is true, return a new string containing all the odd characters.
 # When the boolean is false, return a new string containing all the even characters.
-# 
+#
 # If you have no idea where to begin, remember to check out the cheatsheets for string and logic/control
-# 
+#
 # odds_and_evens("abcdefg",true)    # => "bdf"
 # odds_and_evens("abcdefg",false)   # => "aceg"
 
 def odds_and_evens(string, return_odds)
+  string.chars.select.with_index{|_, i| return_odds ? i.odd? : i.even?}
 end
diff --git a/session1/challenge/7_string.rb b/session1/challenge/7_string.rb
index 4d4ea2a8..801545a0 100644
--- a/session1/challenge/7_string.rb
+++ b/session1/challenge/7_string.rb
@@ -1,8 +1,22 @@
 # given a string, return the character after every letter "r"
-# 
+#
 # pirates_say_arrrrrrrrr("are you really learning Ruby?") # => "eenu"
 # pirates_say_arrrrrrrrr("Katy Perry is on the radio!")   # => "rya"
 # pirates_say_arrrrrrrrr("Pirates say arrrrrrrrr")        # => "arrrrrrrr"
 
 def pirates_say_arrrrrrrrr(string)
+  to_return = ""
+  add_next = false
+  string.size.times do |index|
+      current_char = string[index]
+      to_return << current_char if add_next
+      add_next = (current_char == "r" || current_char == "R")
+  end
+  to_return
 end
+
+
+
+#  def pirates_say_arrrrrrrrr(string)
+#      string.gsub(/(?<!r)./i, '')
+#    end
diff --git a/session2/challenge/10_classes.rb b/session2/challenge/10_classes.rb
index de09d09f..9346a963 100644
--- a/session2/challenge/10_classes.rb
+++ b/session2/challenge/10_classes.rb
@@ -16,4 +16,15 @@
 #
 
 class Person
+
+attr_accessor :name, :age
+
+def initialize(name, age)
+  @name = name
+  @age  = age
+end
+
+def birthday
+  @age += 1
+end
 end
diff --git a/session2/challenge/11_classes.rb b/session2/challenge/11_classes.rb
index 8cde90c8..eeefc314 100644
--- a/session2/challenge/11_classes.rb
+++ b/session2/challenge/11_classes.rb
@@ -12,9 +12,50 @@
 # Zero bottles of beer on the wall.
 #
 # Your program should not use ninety-nine output statements!
-# Design your program with a class named BeerSong whose initialize method 
+# Design your program with a class named BeerSong whose initialize method
 # receives a parameter indicating the number of bottles of beer initially on the wall.
 # If the parameter is less than zero, set the number of bottles to zero. Similarly,
 # if the parameter is greater than 99, set the number of beer bottles to 99
 # Then make a public method called print_song that outputs all stanzas from the number of bottles of beer down to zero.
 # Add any additional methods you find helpful.
+
+class BeerSong
+attr_accessor :beers
+
+def initialize(beers)
+  beers = 0 if beers < 0
+  beers = 99 if beers > 99
+  self.beers = beers
+end
+
+def print_song
+  beers.downto 1 do |i|
+    print_stanza i
+  end
+end
+
+def print_stanza(n)
+  if n.zero?
+    String.new
+  else
+    puts "#{translate n} #{bottle n} of beer on the wall,"
+    "#{translate n} #{bottle n} of beer,"
+    "Take on down, pass it around,"
+    "#{translate n - 1} #{bottle n - 1} of beer on the wall."
+  end
+end
+
+def bottle(n)
+  if n == 1 then 'bottle' else 'bottles' end
+  end
+
+  def translate(n)
+    if 0 <= n && n <= 19
+      %w(zero one two three four five six seven eight nine ten eleven twelve thirteen fourteen fiftenn sixteen seventeen eighteen nineteen)
+    elseif n % 10 == 0
+    %w(zero ten twenty thirty forty fifty sixty seventy eigthy ninety)[n/10]
+  else
+    "#{translate n/10*10}-#{translate n%10}".downcase
+  end.capitalize
+end
+end
diff --git a/session2/challenge/1_input_output.rb b/session2/challenge/1_input_output.rb
index 06622c97..5de445d0 100644
--- a/session2/challenge/1_input_output.rb
+++ b/session2/challenge/1_input_output.rb
@@ -3,10 +3,14 @@
 
 # Write a program that reads in two integers typed on the keybaord
 # and outputs their sum, difference, and product
-# 
+#
 # Standard input will be like "9 2\n" and will expect you to print
 # "11\n7\n18\n" to standard output.
 
+
 def sum_difference_product
-  # your code goes here
-end
\ No newline at end of file
+  a , b = gets.split.map { |num| num.to_i }
+  puts a + b
+  puts a - b
+  puts a * b
+end
diff --git a/session2/challenge/2_input_output_control.rb b/session2/challenge/2_input_output_control.rb
index c618f11a..c4f23ab2 100644
--- a/session2/challenge/2_input_output_control.rb
+++ b/session2/challenge/2_input_output_control.rb
@@ -1,5 +1,5 @@
 # Prompt the user for a number, then read it in and print out "hi" that many times
-# 
+#
 # Repeat this process until the user submits "bye", then say "goodbye" and end the program
 # HINT: Check out example 2 if you get stuck
 
@@ -18,14 +18,24 @@
 # remember you can try your program out with              $ ruby 2_input_output_control.rb
 # and when you think it is correct, you can test it with  $ rake 2:2
 
+def prompt
+puts "Enter a number or bye"
+end
+
 def hi_hi_goodbye
-  # your code here
+  prompt
+while (line = gets) && (line !~ /bye/)
+  line.to_i.times { print 'hi ' }
+  puts prompt
 end
+puts "Goodbye"
+end
+
 
 
 
 
 # This will just invoke the method if you run this program directly
-# This way you can try it out by running "$ ruby 2_input_output_control.rb" 
+# This way you can try it out by running "$ ruby 2_input_output_control.rb"
 # but it will still work for our tests
-hi_hi_goodbye if $0 == __FILE__
\ No newline at end of file
+hi_hi_goodbye if $0 == __FILE__
diff --git a/session2/challenge/3_array.rb b/session2/challenge/3_array.rb
index 8fa14a40..42c80c41 100644
--- a/session2/challenge/3_array.rb
+++ b/session2/challenge/3_array.rb
@@ -7,5 +7,10 @@
 
 class String
   def every_other_char
+    to_return = ''
+    each_char.with_index do |char, index|
+      to_return << char if index.even?
+    end
+    to_return
   end
 end
diff --git a/session2/challenge/4_array.rb b/session2/challenge/4_array.rb
index 1f4d1952..d5d19a00 100644
--- a/session2/challenge/4_array.rb
+++ b/session2/challenge/4_array.rb
@@ -7,3 +7,7 @@
 # get_squares [25, 4, 9, 6, 50, 16, 5] # => [4, 5]
 
 # This time you will have to define the method, it's called: get_squares
+
+def get_squares(numbers)
+  numbers.select { |n| numbers.include? n*n }.sort
+end
diff --git a/session2/challenge/5_array.rb b/session2/challenge/5_array.rb
index 2f7de799..98c57f26 100644
--- a/session2/challenge/5_array.rb
+++ b/session2/challenge/5_array.rb
@@ -1,7 +1,7 @@
-# Write a function named mod_three which takes an array of numbers, 
+# Write a function named mod_three which takes an array of numbers,
 # and return a new array consisting of their remainder when divided by three.
 # Exclude any numbers which are actually dividible by three.
-# 
+#
 # EXAMPLES:
 # mod_three [0]  # => []
 # mod_three [1]  # => [1]
@@ -13,3 +13,7 @@
 # mod_three [7]  # => [1]
 #
 # mod_three [0,1,2,3,4,5,6,7] # => [1, 2, 1, 2, 1]
+
+def mod_three(numbers)
+  numbers.select { |number| number % 3 != 0 }.map { |number| % 3 }
+end
diff --git a/session2/challenge/6_array.rb b/session2/challenge/6_array.rb
index a233b0bf..a479687c 100644
--- a/session2/challenge/6_array.rb
+++ b/session2/challenge/6_array.rb
@@ -1,16 +1,30 @@
 # Write a method named prime_chars? which takes array of strings
-# and returns true if the sum of the characters is prime. 
-# 
-# Remember that a number is prime if the only integers that can divide it with no remainder are 1 and itself. 
-# 
+# and returns true if the sum of the characters is prime.
+#
+# Remember that a number is prime if the only integers that can divide it with no remainder are 1 and itself.
+#
 # Examples of length three
 # prime_chars? ['abc']            # => true
 # prime_chars? ['a', 'bc']        # => true
 # prime_chars? ['ab', 'c']        # => true
 # prime_chars? ['a', 'b', 'c']    # => true
-# 
+#
 # Examples of length four
 # prime_chars? ['abcd']           # => false
 # prime_chars? ['ab', 'cd']       # => false
 # prime_chars? ['a', 'bcd']       # => false
 # prime_chars? ['a', 'b', 'cd']   # => false
+
+class Integer
+  def prime?
+    return false if self < 2
+    2.upto Math.sqrt(self) do |i|
+      return false if self % i == 0
+    end
+    true
+  end
+end
+
+def prime_chars?(strings)
+  strings.join.length.prime?
+end
diff --git a/session2/challenge/7_array.rb b/session2/challenge/7_array.rb
index 346f8307..200c9ec2 100644
--- a/session2/challenge/7_array.rb
+++ b/session2/challenge/7_array.rb
@@ -3,8 +3,21 @@
 # In order to not have to write an actual language parser, there won't be any punctuation too complex.
 # There will be no "'" that is not part of a contraction.
 # Assume each of these  charactsrs are not to be considered: ! @ $ # % ^ & * ( ) - = _ + [ ] : ; , . / < > ? \ |
-# 
+#
 # Examples
 # alternate_words("Lorem ipsum dolor sit amet.")  # => ["Lorem", "dolor", "amet"]
 # alternate_words("Can't we all get along?")      # => ["Can't", "all", "along"]
 # alternate_words("Elementary, my dear Watson!")  # => ["Elementary", "dear"]
+
+def alternate_words(sentence)
+  # this will get better when we learn regular expressions :)
+  '!@$#%^&*()-=_+[]:;,./<>?\\|'.split(//).each do |char|
+    sentence = sentence.gsub(char, ' ')
+  end
+  words = sentence.split
+  solution = []
+  words.each_with_index do |word, index|
+    solution << word if index.even?
+  end
+  solution
+end
diff --git a/session2/challenge/8_array.rb b/session2/challenge/8_array.rb
index 860850a0..81ab94aa 100644
--- a/session2/challenge/8_array.rb
+++ b/session2/challenge/8_array.rb
@@ -1,7 +1,14 @@
 # Given an array of elements, return true if any element shows up three times in a row
-# 
+#
 # Examples:
 # got_three? [1, 2, 2, 2, 3]  # => true
 # got_three? ['a', 'a', 'b']  # => false
 # got_three? ['a', 'a', 'a']  # => true
 # got_three? [1, 2, 1, 1]     # => false
+
+def got_three?(elements)
+  elements.each_cons 3 do |a, b, c|
+    return true if a == b && b == c
+  end
+  false
+end
diff --git a/session2/challenge/9_input_output_logic_string.rb b/session2/challenge/9_input_output_logic_string.rb
index 626119b3..2ff47300 100644
--- a/session2/challenge/9_input_output_logic_string.rb
+++ b/session2/challenge/9_input_output_logic_string.rb
@@ -23,14 +23,28 @@
 # GRANDMA:  HUH?! SPEAK UP, SONNY!
 # USER:     BYE
 
-def deaf_grandma
+def prompt
+puts "Say hi to your grandma!"
+end
 
+def deaf_grandma
+  prompt
+  while line = gets
+    line.chomp!
+    break if line == "BYE"
+    if line == line.upcase && line != ""
+      puts "NO, NOT SINCE 1938!"
+    else
+      puts "HUH?! SPEAK UP, SONNY!"
+    end
+  end
 end
 
 
 
 
 
+
 # This will call your code so you can run it from the terminal.
 # But not call it otherwise, so that it will work with our tests.
 deaf_grandma if $0 == __FILE__