diff --git a/01-hello.rb b/01-hello.rb
index e0e7bbf..a637b8c 100644
--- a/01-hello.rb
+++ b/01-hello.rb
@@ -5,4 +5,4 @@
 
 # ...
 
-puts "(请替换成最后的答案)"
\ No newline at end of file
+puts "hello #{your_name}"
diff --git a/02-variable.rb b/02-variable.rb
index a5a4753..07e89c1 100644
--- a/02-variable.rb
+++ b/02-variable.rb
@@ -7,7 +7,7 @@
 puts "b 是 #{b}"
 
 # ...
+a, b = b, a
 
 puts "a 应该是 2，现在是 #{a}"
 puts "b 应该是 1，现在是 #{b}"
-
diff --git a/03-triangle.rb b/03-triangle.rb
index fafec03..0e9dc57 100644
--- a/03-triangle.rb
+++ b/03-triangle.rb
@@ -7,5 +7,6 @@
 b = gets
 
 # .....
+s = (a.to_f * b.to_f) / 2
 
-puts "直角三角形的面积是: _________"
\ No newline at end of file
+puts "直角三角形的面积是: ____#{s}_____"
diff --git a/04-pizzas.rb b/04-pizzas.rb
index 4c2521f..740a16b 100644
--- a/04-pizzas.rb
+++ b/04-pizzas.rb
@@ -7,6 +7,8 @@
 people = gets
 
 # .....
+a = pizzas.to_i / people.to_i
+b = pizzas.to_i % people.to_i
 
-puts "每人可分得几片: _________ 片"
-puts "还剩下几片: _________ 片"
\ No newline at end of file
+puts "每人可分得几片: _____#{a}____ 片"
+puts "还剩下几片: ____#{b}_____ 片"
diff --git a/05-bmi.rb b/05-bmi.rb
index 67efdff..2f0972c 100644
--- a/05-bmi.rb
+++ b/05-bmi.rb
@@ -6,12 +6,22 @@
 
 print "请输入您的体重(公斤)，然后按 Enter: "
 weight = gets
+weight = weight.to_f
 
 print "请输入您的身高(厘米)，然后按 Enter: "
 height = gets
-
+height = height.to_f
 # .....
+bmi = weight / ( height ** 2 )
+
+if bmi < 18.5
+  result = "过轻"
+elsif bmi >= 24
+  result = "过重"
+else
+  result = "正常"
+end
 
-puts "您的 BMI 是: _________"
+puts "您的 BMI 是: ____#{bmi}_____"
 
-puts "您的 BMI 结果是: _________(过轻或正常或过重)"
\ No newline at end of file
+puts "您的 BMI 结果是: _____#{result}____(过轻或正常或过重)"
diff --git a/06-interger-positive.rb b/06-interger-positive.rb
index a240f5f..ae804fc 100644
--- a/06-interger-positive.rb
+++ b/06-interger-positive.rb
@@ -3,8 +3,18 @@
 
 print "请输入一个整数，然后按 Enter: "
 x = gets
-
+x = x.to_i
 # ....
 
-puts "这个数是_____ (正数或零或负数)"
-puts "这个数是_____ (偶数或奇数)"
\ No newline at end of file
+if x == 0
+  result1 = "零"
+elsif x > 0
+  result1 = "正数"
+else
+  result1 = "负数"
+end
+
+result2 = (x % 2 == 0) ? "偶数" : "奇数"
+
+puts "这个数是___#{result1}__ (正数或零或负数)"
+puts "这个数是__#{result2}___ (偶数或奇数)"
diff --git a/07-abcde.rb b/07-abcde.rb
index 5d0c8c3..c9a662f 100644
--- a/07-abcde.rb
+++ b/07-abcde.rb
@@ -10,13 +10,25 @@
 
 print "请输入一个整数x，然后按 Enter: "
 x = gets
+x = x.to_i
 
 print "请输入一个整数y，然后按 Enter: "
 y = gets
+y = y.to_i
 
 print "请输入一个整数z，然后按 Enter: "
 z = gets
+z = z.to_i
 
 # ....
+if x > 0
+  if y > 0
+    result = (z > 0) ? "B" : "C"
+  else
+    result = (z > 0) ? "D" : "E"
+  end
+else
+  result = "A"
+end
 
-puts "结果是________(A或B或C或D或E)"
\ No newline at end of file
+puts "结果是____#{result}____(A或B或C或D或E)"
diff --git a/08-find-max.rb b/08-find-max.rb
index 9e6e643..c64c6db 100644
--- a/08-find-max.rb
+++ b/08-find-max.rb
@@ -8,7 +8,8 @@
 
 print "请输入一个数字z，然后按 Enter: "
 z = gets
-
 # ....
 
-puts "最大的数是 ________(x或y或z)"
\ No newline at end of file
+result = [x, y, z].map(&:to_i).max
+
+puts "最大的数是 ___#{result}_____(x或y或z)"
diff --git a/09-function.rb b/09-function.rb
index b1f922d..d265f90 100644
--- a/09-function.rb
+++ b/09-function.rb
@@ -2,14 +2,17 @@
 
 def calculate_area(a, b)
   # ....
+  (a * b) / 2
 end
 
 print "请输入直角三角形的高，然后按 Enter: "
 a = gets
+a = a.to_f
 
 print "请输入直角三角形的底边，然后按 Enter: "
 b = gets
+b = b.to_f
 
 answer = calculate_area(a,b)
 
-puts "直角三角形的面积是: #{answer}"
\ No newline at end of file
+puts "直角三角形的面积是: #{answer}"
diff --git a/10-function.rb b/10-function.rb
index bb450fb..9fbcfef 100644
--- a/10-function.rb
+++ b/10-function.rb
@@ -1,6 +1,7 @@
 # 题目: 使用者输入 x,y,z，请输出三个数中最大的数
 
 def find_max(x, y, z)
+  [x, y, z].map(&:to_i).max
 end
 
 print "请输入一个数字x，然后按 Enter: "
@@ -16,4 +17,4 @@ def find_max(x, y, z)
 
 answer = find_max(x,y,z)
 
-puts "最大的数是 #{answer}"
\ No newline at end of file
+puts "最大的数是 #{answer}"
diff --git a/11-seven.rb b/11-seven.rb
index 26c221d..0eb905d 100644
--- a/11-seven.rb
+++ b/11-seven.rb
@@ -4,6 +4,9 @@
 while ( i <= 100 )
 
   # ....
+  if i % 7 == 0
+    puts i
+  end
 
   i+=1
-end
\ No newline at end of file
+end
diff --git a/12-sum-even.rb b/12-sum-even.rb
index 73879bb..c25767f 100644
--- a/12-sum-even.rb
+++ b/12-sum-even.rb
@@ -6,8 +6,11 @@
 while ( i <= 100 )
 
   # ....
+  if i % 2 == 0
+    total += i
+  end
 
   i+=1
 end
 
-puts total
\ No newline at end of file
+puts total
diff --git a/13-nn.rb b/13-nn.rb
index ac0a43b..b153cb5 100644
--- a/13-nn.rb
+++ b/13-nn.rb
@@ -2,6 +2,7 @@
 
 print "请输入数字 N，然后按 Enter: "
 n = gets
+n = n.to_i
 
 # while ( ... )
 #   while ( ...)
@@ -9,3 +10,12 @@
 #   end
 # end
 
+i = 1
+while ( i <= n )
+  h = 1
+  while ( h <= n )
+    puts "#{i} * #{h} = #{i * h}" 
+    h += 1
+  end
+  i += 1
+end
diff --git a/14-prime.rb b/14-prime.rb
index 8cf1692..fc8f2f1 100644
--- a/14-prime.rb
+++ b/14-prime.rb
@@ -1,7 +1,19 @@
 # 输入一个数字 N，请检查是不是质数
 
 def is_prime(n)
-# ....
+  if n < 2
+    return false
+  elsif n == 2
+    return true
+  else
+    for i in 2..n-1
+      if n % i == 0
+        return false
+      else
+        return true
+      end
+    end
+  end
 end
 
 print "请输入数字 N，然后按 Enter: "
diff --git a/15-guess-number.rb b/15-guess-number.rb
index 48f9dca..869ea53 100644
--- a/15-guess-number.rb
+++ b/15-guess-number.rb
@@ -6,12 +6,13 @@
   print "请猜一个 0~99 的数字 N，然后按 Enter: "
   n = gets
 
-  #puts "太低了，再猜一次"
-  #puts "太高了，再猜一次"
-
   if n.to_i == target
     puts "恭喜猜中啦! "
     break
+  elsif n.to_i > target
+    puts "太高了，再猜一次"
+  else
+    puts "太低了，再猜一次"
   end
 
-end
\ No newline at end of file
+end
diff --git a/16-array-sum.rb b/16-array-sum.rb
index 9b4910b..76bcd3c 100644
--- a/16-array-sum.rb
+++ b/16-array-sum.rb
@@ -1,11 +1,16 @@
 # 给定一阵列内含数字，输出最大值
 
 def find_max(array)
-  #....
+  m = array[0]
+  for i in 1..((array.length)-1)
+    if array[i] > m
+      m = array[i]
+    end
+  end
+  m
 end
 
 arr = [8, 12, 36, 53, 9, 75, 3, 71, 59, 88]
 
 max = find_max(arr)
 puts "Max is #{max}" # 应该是 88
-
diff --git a/17-array-stats.rb b/17-array-stats.rb
index 0af81bb..e92cecb 100644
--- a/17-array-stats.rb
+++ b/17-array-stats.rb
@@ -1,6 +1,7 @@
 # 使用者不断输入数字存进 Array，最后输出总和、平均、最大值、最小值
 
 arr = []
+total = 0
 
 while (true)
   print "请输入数字，结束请直接按 Enter: "
@@ -12,9 +13,16 @@
   end
 end
 
+for i in arr
+  total += i
+end
+
 puts arr.to_s
+average = total.to_f / arr.length
+max = arr.max
+min = arr.min
 
-puts "总和是 _____"
-puts "平均是 _____"
-puts "最大值是 _____"
-puts "最小值是 _____"
\ No newline at end of file
+puts "总和是 __#{total}___"
+puts "平均是 __#{average}___"
+puts "最大值是 ___#{max}__"
+puts "最小值是 ___#{min}__"
diff --git a/18-square.rb b/18-square.rb
index 226e1c1..9eb4161 100644
--- a/18-square.rb
+++ b/18-square.rb
@@ -4,7 +4,11 @@
 
 print "请输入数字 N，然后按 Enter: "
 n = gets
+n = n.to_i
 
+for i in 0..n-1
+  arr << i ** 2
+end
 # ...
 
-puts arr.to_s
\ No newline at end of file
+puts arr.to_s
diff --git a/19-filter.rb b/19-filter.rb
index ef7e515..dcd2112 100644
--- a/19-filter.rb
+++ b/19-filter.rb
@@ -1,9 +1,15 @@
 # 给定一阵列内含数字，输出另一个数组只包含偶数
 
 def filter_even(arr)
-  #...
+  result = []
+  for i in arr
+    if i % 2 == 0
+      result << i
+    end
+  end
+  result
 end
 
 arr =  [7, 68, 42, 46, 9, 91, 77, 46, 86, 1]
 
-puts filter_even(arr).to_s # 应该是 [68, 42, 46, 46, 86]
\ No newline at end of file
+puts filter_even(arr).to_s # 应该是 [68, 42, 46, 46, 86]
diff --git a/20-sorting.rb b/20-sorting.rb
index 5f82c08..dc47359 100644
--- a/20-sorting.rb
+++ b/20-sorting.rb
@@ -2,10 +2,16 @@
 # Hint: 可用 arr.sort 排序，和 arr.uniq 去除重复
 
 def filter_even(arr)
-  #...
+  result = []
+  for i in arr
+    if i % 2 == 0
+      result << i
+    end
+  end
+  result.sort.uniq
 end
 
 arr =  [7, 68, 42, 46, 9, 91, 77, 46, 86, 1]
 
 
-puts "________" # 应该是 [42, 46, 68, 86]
\ No newline at end of file
+puts filter_even(arr).to_s # 应该是 [42, 46, 68, 86]
diff --git a/21-selection-sort.rb b/21-selection-sort.rb
index 9cb58f8..1b4f1eb 100644
--- a/21-selection-sort.rb
+++ b/21-selection-sort.rb
@@ -2,11 +2,19 @@
 # https://zh.wikipedia.org/wiki/选择排序
 
 def insertion_sort(arr)
-  #...
+  return arr if arr.length == 0
+  (0..arr.length-1).each do |i|
+    min, index = arr[i], i
+    (i+1..arr.length-1).each do |j|
+      min, index = arr[j], j if arr[j] < min
+      arr[i], arr[index] = arr[index], arr[i]
+    end
+  end
+  arr
 end
 
 arr =  [7, 68, 42, 46, 9, 91, 77, 46, 86, 1]
 
 answer = insertion_sort(arr)
 
-puts answer.to_s # 应该是 [1, 7, 9, 42, 46, 46, 68, 77, 86, 91]
\ No newline at end of file
+puts answer.to_s # 应该是 [1, 7, 9, 42, 46, 46, 68, 77, 86, 91]
diff --git a/22-missing.rb b/22-missing.rb
index 6898714..c6a624e 100644
--- a/22-missing.rb
+++ b/22-missing.rb
@@ -1,7 +1,12 @@
 # 给定一阵列内含数字，请输出 0~9 中不见的数字
 
 def find_missing(arr)
-  # ...
+  arr.uniq
+  result = []
+  for i in 0..9
+    result << i if !arr.include?(i)
+  end
+  result
 end
 
 answer = find_missing( [2,2,1,5,8,4] )
diff --git a/23-hash-max.rb b/23-hash-max.rb
index 6fb227e..c229f7f 100644
--- a/23-hash-max.rb
+++ b/23-hash-max.rb
@@ -1,7 +1,8 @@
 # 给定一 Hash，输出有最大 value 的 key
 
 def find_max(hash)
-  # ...
+  result = hash.values.max
+  hash::key(result)
 end
 
 h = {
@@ -15,5 +16,3 @@ def find_max(hash)
 answer = find_max(h)
 
 puts "有最大 value 的是 #{answer}" # 应该是 d
-
-
diff --git a/24-hash-even.rb b/24-hash-even.rb
index 9da9605..9c5fbf4 100644
--- a/24-hash-even.rb
+++ b/24-hash-even.rb
@@ -1,9 +1,16 @@
 # 给定一 Hash，输出 value 是偶数的 keys
 
 def find_even_keys(hash)
-
-  # ... (请回传一个数组)
-
+  result1 = []
+  h = hash.values
+  for i in h
+    result1 << i if i % 2 == 0
+  end
+  result2 = []
+  for j in result1
+    result2 << hash::key(j)
+  end
+  result2
 end
 
 h = {
@@ -17,5 +24,3 @@ def find_even_keys(hash)
 answer = find_even_keys(h)
 
 puts "有偶数 value 的 keys 有 #{answer}" # 应该是数组 [b,d,e]
-
-
diff --git a/25-hash-count.rb b/25-hash-count.rb
index 2167335..c7c631a 100644
--- a/25-hash-count.rb
+++ b/25-hash-count.rb
@@ -2,11 +2,10 @@
 
 def count(arr)
   h = {}
-
-  arr.each do |i|
-    # ...
+  arr.uniq.each do |i|
+    a = arr.count(i)
+    h[i] = a
   end
-
   return h # 回传一个 hash
 end
 
@@ -15,4 +14,3 @@ def count(arr)
 answer = count(arr)
 
 puts answer # 答案应该是 {"a"=>3, "d"=>6, "c"=>5, "b"=>1, "e"=>5}
-
diff --git a/26-hash-filter.rb b/26-hash-filter.rb
index 51ade64..b0c58b8 100644
--- a/26-hash-filter.rb
+++ b/26-hash-filter.rb
@@ -7,10 +7,23 @@
   { "name" => "Steven", "age" => 22 },
   { "name" => "Vincent", "age" => 6 },
 ]
+h = []
+arr.each do |a|
+  if a["age"] > 18
+    h << a
+  end
+  h
+end
 
-# ....
+(0..h.length-1).each do |i|
+  min, index = h[i], i
+  (i+1..h.length-1).each do |j|
+    min, index = h[j], j if h[j]["age"] < min["age"]
+    h[i], h[index] = h[index], h[i]
+  end
+end
 
-puts "所有成年人，并由小到大: _________"
+puts "所有成年人，并由小到大: _____#{h}____"
 
 # 答案应该是
 #[
diff --git a/27-class.rb b/27-class.rb
index 8cec2c9..91b9331 100644
--- a/27-class.rb
+++ b/27-class.rb
@@ -1,5 +1,8 @@
 class Person
-  # ...
+  attr_accessor :first_name, :last_name
+  def greet
+    puts "Hello, #{first_name} #{last_name}"
+  end
 end
 
 p1 = Person.new
@@ -11,6 +14,3 @@ class Person
 p2.first_name = "William"
 p2.last_name = "Zhang"
 p2.greet # 输出 "Hello, William Zhang"
-
-
-
diff --git a/28-word-count.rb b/28-word-count.rb
index 2643123..5e400ac 100644
--- a/28-word-count.rb
+++ b/28-word-count.rb
@@ -1,5 +1,18 @@
 # 请打开 wordcount.txt，计算每个单字出现的次数
 
 doc = File.read("wordcount.txt")
+word_count = Hash.new(0)
+doc.each_line do |line|
+  line = line.gsub(/[,'".]/,'')
+  words = line.split
+  words.each do |word|
+    word_count[word] += 1
+  end
+end
 
+puts '每个单词出现的频数为：'
+
+word_count.each do |key, value|
+  puts "#{key} #{value}"
+end
 # ...
diff --git a/29-todos.rb b/29-todos.rb
index 0bddde2..8df0922 100644
--- a/29-todos.rb
+++ b/29-todos.rb
@@ -14,16 +14,29 @@
 while (true)
   print "请输入指令 1. add 2. remove 3. save，然后按 Enter: "
   command = gets.chomp
-
   if command == "add"
     print "请输入代办事项: "
+    task = gets.chomp
+    todos << task
+    todos.each_with_index do |todo, index|
+      puts "#{index}: #{todo}"
+    end
     # ...
   elsif command == "remove"
     print "请输入要删除的编号: "
+    todos.delete_at(gets.chomp.to_i)
+    todos.each_with_index do |todo, index|
+      puts "#{index}: #{todo}"
+    end
     # ...
   elsif command == "save"
     puts "存盘离开"
-
+    File.open("todos.txt", "w+") do |f|
+      todos.each do |todo|
+        f << todo
+        f << "\n"
+      end
+    end
     # ...
     break;
   else
diff --git a/_config.yml b/_config.yml
new file mode 100644
index 0000000..c741881
--- /dev/null
+++ b/_config.yml
@@ -0,0 +1 @@
+theme: jekyll-theme-slate
\ No newline at end of file
diff --git a/todos.txt b/todos.txt
index 4757e85..ea6b63f 100644
--- a/todos.txt
+++ b/todos.txt
@@ -2,3 +2,4 @@ Buy book
 Go Shopping
 Walk
 Gogo
+Cake