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..677c809 100644
--- a/02-variable.rb
+++ b/02-variable.rb
@@ -6,8 +6,11 @@
 puts "a 是 #{a}"
 puts "b 是 #{b}"
 
-# ...
+c = a
+
+a = b
+
+b = c
 
 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..8d6b42a 100644
--- a/03-triangle.rb
+++ b/03-triangle.rb
@@ -6,6 +6,9 @@
 print "请输入直角三角形的底边，然后按 Enter: "
 b = gets
 
+c = a.to_f * b.to_f
+
+c = c / 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: __#{c}___"
diff --git a/04-pizzas.rb b/04-pizzas.rb
index 4c2521f..62da0e1 100644
--- a/04-pizzas.rb
+++ b/04-pizzas.rb
@@ -8,5 +8,9 @@
 
 # .....
 
-puts "每人可分得几片: _________ 片"
-puts "还剩下几片: _________ 片"
\ No newline at end of file
+a=pizzas.to_i/people.to_i
+
+b=pizzas.to_i%people.to_i
+
+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..6b1605d 100644
--- a/05-bmi.rb
+++ b/05-bmi.rb
@@ -10,8 +10,20 @@
 print "请输入您的身高(厘米)，然后按 Enter: "
 height = gets
 
+w = weight.to_f
+h = height.to_f/100
+b = w/h
+b = b/h
+
+if b < 18.5
+	a = "过轻"
+elsif b >= 24
+	a = "过重"
+else
+	a = "正常"
+end
 # .....
 
-puts "您的 BMI 是: _________"
+puts "您的 BMI 是: ____#{b}_____"
 
-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: ____#{a}_____(过轻或正常或过重)"
diff --git a/06-interger-positive.rb b/06-interger-positive.rb
index a240f5f..61b1d7f 100644
--- a/06-interger-positive.rb
+++ b/06-interger-positive.rb
@@ -3,8 +3,21 @@
 
 print "请输入一个整数，然后按 Enter: "
 x = gets
-
 # ....
+x = x.to_i
+if x > 0
+	a = "正数"
+elsif x < 0
+	a = "负数"
+else
+	a = "0"
+end
+
+if x%2 != 0
+	b = "奇数"
+else
+	b = "偶数"
+end
 
-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
+puts "这个数是__#{a}___ (正数或零或负数)"
+puts "这个数是___#{b}__ (偶数或奇数)"
diff --git a/07-abcde.rb b/07-abcde.rb
index 5d0c8c3..58155d5 100644
--- a/07-abcde.rb
+++ b/07-abcde.rb
@@ -17,6 +17,27 @@
 print "请输入一个整数z，然后按 Enter: "
 z = gets
 
+x = x.to_i
+y = y.to_i
+z = z.to_i
+
+if x < 0
+	a = "A"
+else
+	if y > 0
+		if z > 0
+			a = "B"
+		else
+			a = "C"
+		end
+	else
+		if z > 0
+			a = "D"
+		else
+			a = "E"
+		end
+	end
+end
 # ....
 
-puts "结果是________(A或B或C或D或E)"
\ No newline at end of file
+puts "结果是____#{a}____(A或B或C或D或E)"
diff --git a/08-find-max.rb b/08-find-max.rb
index 9e6e643..1008b62 100644
--- a/08-find-max.rb
+++ b/08-find-max.rb
@@ -9,6 +9,18 @@
 print "请输入一个数字z，然后按 Enter: "
 z = gets
 
+x = x.to_f
+y = y.to_f
+z = z.to_f
+
+if x >= y && x >= z
+	a = "x"
+elsif y >= x && y >= z
+	a = "y"
+else
+	a = "z"
+end
+
 # ....
 
-puts "最大的数是 ________(x或y或z)"
\ No newline at end of file
+puts "最大的数是 ___#{a}_____(x或y或z)"
diff --git a/09-function.rb b/09-function.rb
index b1f922d..f44dc1d 100644
--- a/09-function.rb
+++ b/09-function.rb
@@ -2,6 +2,7 @@
 
 def calculate_area(a, b)
   # ....
+	c =(a.to_f*b.to_f)/2
 end
 
 print "请输入直角三角形的高，然后按 Enter: "
@@ -12,4 +13,4 @@ def calculate_area(a, b)
 
 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..475eab9 100644
--- a/10-function.rb
+++ b/10-function.rb
@@ -1,6 +1,17 @@
 # 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=x.to_f
+	y=y.to_f
+	z=z.to_f
+
+	if x>y && y>z
+		x
+	elsif y>z
+		y
+	else
+		z
+	end
 end
 
 print "请输入一个数字x，然后按 Enter: "
@@ -16,4 +27,4 @@ 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..ec2771a 100644
--- a/11-seven.rb
+++ b/11-seven.rb
@@ -3,7 +3,11 @@
 i = 1
 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..703fb0e 100644
--- a/12-sum-even.rb
+++ b/12-sum-even.rb
@@ -5,9 +5,13 @@
 
 while ( i <= 100 )
 
-  # ....
+  if i%2 == 0
+
+    total = 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..f7a4601 100644
--- a/13-nn.rb
+++ b/13-nn.rb
@@ -3,9 +3,17 @@
 print "请输入数字 N，然后按 Enter: "
 n = gets
 
-# while ( ... )
-#   while ( ...)
-#
-#   end
-# end
+n = n.to_i
 
+a=1
+b=1
+
+while (a<=n)
+   	while (b<=n)
+			print "#{a*b}  "
+			b=b+1
+   	end
+		b=1
+		a=a+1
+		puts
+end
diff --git a/14-prime.rb b/14-prime.rb
index 8cf1692..4a3f4a5 100644
--- a/14-prime.rb
+++ b/14-prime.rb
@@ -1,6 +1,16 @@
 # 输入一个数字 N，请检查是不是质数
 
 def is_prime(n)
+  n=n.to_i
+  i=2
+  while i<=n/2
+    if n % i ==0
+      return false
+    else
+      i = i + 1
+    end
+  end
+  true
 # ....
 end
 
diff --git a/15-guess-number.rb b/15-guess-number.rb
index 48f9dca..1fd8b7f 100644
--- a/15-guess-number.rb
+++ b/15-guess-number.rb
@@ -5,13 +5,16 @@
 while (true)
   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"
-
+  n=n.to_i
+  if n<target
+    puts "太低了，再猜一次"
+  end
+  if n>target
+    puts "太高了，再猜一次"
+  end
   if n.to_i == target
     puts "恭喜猜中啦! "
     break
   end
 
-end
\ No newline at end of file
+end
diff --git a/16-array-sum.rb b/16-array-sum.rb
index 9b4910b..4980b2d 100644
--- a/16-array-sum.rb
+++ b/16-array-sum.rb
@@ -2,10 +2,18 @@
 
 def find_max(array)
   #....
+	i=0
+	m=0
+	while i <(array.length)
+		if m<array[i]
+			m=array[i]
+		end
+		i=i+1
+	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..64a4e03 100644
--- a/17-array-stats.rb
+++ b/17-array-stats.rb
@@ -11,10 +11,15 @@
     arr << user_input.to_i
   end
 end
+total = 0
+arr.each{|a| total += a}
+ave = total.to_f/arr.length
+max = arr.max
+min = arr.min
 
 puts arr.to_s
 
-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 ___#{ave}__"
+puts "最大值是 ___#{max}__"
+puts "最小值是 ___#{min}__"
diff --git a/18-square.rb b/18-square.rb
index 226e1c1..f372b8d 100644
--- a/18-square.rb
+++ b/18-square.rb
@@ -4,7 +4,12 @@
 
 print "请输入数字 N，然后按 Enter: "
 n = gets
-
+n=n.to_i
+i = 0
+while i<=n
+	arr[i]=i ** 2
+	i=i+1
+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..945edfb 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)
-  #...
+	newarr = []
+	for a in arr
+		if a%2==0
+			newarr.push(a)
+		end
+	end
+	newarr
 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..c99d5f0 100644
--- a/20-sorting.rb
+++ b/20-sorting.rb
@@ -3,9 +3,17 @@
 
 def filter_even(arr)
   #...
+	newarr = []
+	for a in arr
+		if a%2==0
+			newarr.push(a)
+		end
+	end
+	newarr.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)}" # 应该是 [42, 46, 68, 86]
diff --git a/21-selection-sort.rb b/21-selection-sort.rb
index e5e7eae..174d371 100644
--- a/21-selection-sort.rb
+++ b/21-selection-sort.rb
@@ -2,6 +2,20 @@
 # https://zh.wikipedia.org/wiki/选择排序
 
 def selection_sort(arr)
+  for i in 0..arr.length-1
+     min = i
+     for j in i+1..arr.length-1
+       if arr[min]>arr[j]
+         temp = arr[min]
+         arr[min] = arr[j]
+         arr[j] = temp
+       end
+       j += 1
+     end
+     i += 1
+   end
+   arr
+
   #...
 end
 
@@ -9,4 +23,4 @@ def selection_sort(arr)
 
 answer = selection_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..f745f9b 100644
--- a/22-missing.rb
+++ b/22-missing.rb
@@ -1,7 +1,21 @@
 # 给定一阵列内含数字，请输出 0~9 中不见的数字
 
 def find_missing(arr)
-  # ...
+  # ...   missingArr = []
+	missingArr = []
+    for i in 0..9
+      missing = true
+      for a in arr
+        if a == i
+          missing = false
+          break
+        end
+      end
+      if missing
+        missingArr.push(i)
+      end
+    end
+    missingArr
 end
 
 answer = find_missing( [2,2,1,5,8,4] )
diff --git a/23-hash-max.rb b/23-hash-max.rb
index 6fb227e..de11cbe 100644
--- a/23-hash-max.rb
+++ b/23-hash-max.rb
@@ -2,6 +2,15 @@
 
 def find_max(hash)
   # ...
+     max_value = hash.values.max
+    max_key = ""
+    hash.each do |key,value|
+      if value == max_value
+        max_key = key
+        break
+      end
+    end
+    max_key
 end
 
 h = {
@@ -15,5 +24,3 @@ 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..5a3d0c3 100644
--- a/24-hash-even.rb
+++ b/24-hash-even.rb
@@ -4,6 +4,15 @@ def find_even_keys(hash)
 
   # ... (请回传一个数组)
 
+    even_keys = []
+   hash.each do |key,value|
+     if value % 2 == 0
+       even_keys.push(key)
+     end
+   end
+   even_keys
+
+
 end
 
 h = {
@@ -17,5 +26,3 @@ 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..2cb3b20 100644
--- a/25-hash-count.rb
+++ b/25-hash-count.rb
@@ -4,6 +4,12 @@ def count(arr)
   h = {}
 
   arr.each do |i|
+        if h[i]
+       h[i] += 1
+     else
+       h[i] = 1
+     end
+
     # ...
   end
 
@@ -15,4 +21,3 @@ 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..ac0528e 100644
--- a/26-hash-filter.rb
+++ b/26-hash-filter.rb
@@ -7,10 +7,23 @@
   { "name" => "Steven", "age" => 22 },
   { "name" => "Vincent", "age" => 6 },
 ]
-
+ ages = []
+  arr.each do |h|
+    ages.push(h["age"])
+  end
+  ages = ages.sort
+  newArr = []
+  for age in ages
+    arr.each do |h|
+      if age == h["age"]
+        newArr.push(h)
+        break
+      end
+    end
+  end
 # ....
 
-puts "所有成年人，并由小到大: _________"
+puts "所有成年人，并由小到大: ___#{newArr}______"
 
 # 答案应该是
 #[
diff --git a/27-class.rb b/27-class.rb
index 8cec2c9..b61f17b 100644
--- a/27-class.rb
+++ b/27-class.rb
@@ -1,5 +1,9 @@
 class Person
-  # ...
+	   attr_accessor :first_name,:last_name
+		 
+    def greet
+      puts "Hi, #{first_name} #{last_name}"
+    end
 end
 
 p1 = Person.new
@@ -11,6 +15,3 @@ 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..052d2dc 100644
--- a/28-word-count.rb
+++ b/28-word-count.rb
@@ -3,3 +3,14 @@
 doc = File.read("wordcount.txt")
 
 # ...
+ doc = doc.split(" ")
+  h = {}
+  doc.each do |word|
+    if h[word]
+      h[word]  += 1
+    else
+      h[word] = 1
+    end
+  end
+ 
+  puts h
diff --git a/29-todos.rb b/29-todos.rb
index 0bddde2..54218f8 100644
--- a/29-todos.rb
+++ b/29-todos.rb
@@ -16,18 +16,27 @@
   command = gets.chomp
 
   if command == "add"
-    print "请输入代办事项: "
-    # ...
-  elsif command == "remove"
-    print "请输入要删除的编号: "
-    # ...
-  elsif command == "save"
-    puts "存盘离开"
-
-    # ...
-    break;
-  else
-    puts "看不懂，请再输入一次"
-  end
-end
+     print "请输入代办事项: "
+     # ...
+     newTodo = gets.chomp
+     todos.push(newTodo)
+   elsif command == "remove"
+     print "请输入要删除的编号: "
+     # ...
+     index = gets.chomp.to_i
+     todos.pop(index)
+   elsif command == "save"
+     puts "存盘离开"
 
+     File.open("todos.txt", "w ") do |f|
+       todos.each do |line|
+          f << line
+          f << "\n"
+       end
+     end
+     # ...
+     break;
+   else
+     puts "看不懂，请再输入一次"
+   end
+ end