diff --git a/lib/tree.rb b/lib/tree.rb
index c0d4b51..4729804 100644
--- a/lib/tree.rb
+++ b/lib/tree.rb
@@ -1,13 +1,13 @@
 class TreeNode
-  attr_reader :key, :value
+  attr_reader :key, :value #key(what your using to sort) #value(value in node)
   attr_accessor :left, :right
-
-   def initialize(key, val)
+  
+  def initialize(key, val)
     @key = key
     @value = val
     @left = nil
     @right = nil
-   end
+  end
 end
 
 class Tree
@@ -15,50 +15,149 @@ class Tree
   def initialize
     @root = nil
   end
-
+  
   # Time Complexity: 
   # Space Complexity: 
+  # def add(key, value)
+  #   if @root.nil?
+  #     @root = Node.new(key, value)
+  #   else
+  #     current = @root
+  
+  #     while true
+  #       if key < current.key
+  #         if !current.left.nil?
+  #           current = current.left
+  #         else
+  #           current.left = TreeNode.new(key, value)
+  #         end
+  #       else
+  #         if !current.right.nil?
+  #           current = current.right
+  #         else
+  #           current.right = TreeNode.new(key, value)
+  #           return
+  #         end
+  #       end
+  #     end
+  #   end
+  
+  def add_helper(current_node, key, value)
+    return TreeNode.new(key, value) if current_node.nil?
+    
+    if key < current_node.key
+      current_node.left = add_helper(current_node.left, key, value)
+    else
+      current_node.right = add_helper(current_node.right, key, value)
+    end
+    
+    return current_node
+  end  
+  
   def add(key, value)
-    raise NotImplementedError
+    @root = add_helper(@root, key, value) #starts at root
   end
-
+  
+  
+  
+  
+  def find_helper(current_node, key)
+    return if current_node.nil?
+    
+    return current_node.value if current_node.key == key
+    
+    if key < current_node.key 
+      find_helper(current_node.left, key)
+    else 
+      find_helper(current_node.right, key)
+    end
+  end
+  
   # Time Complexity: 
   # Space Complexity: 
   def find(key)
-    raise NotImplementedError
+    find_helper(@root, key)
+  end
+  
+  # 
+  
+  def inorder_helper(current_node, list)
+    return list if current_node.nil?
+    #get left subtree
+    inorder_helper(current_node.left, list)
+    list << { key: current_node.key, value: current_node.value }
+    #get right subtree
+    inorder_helper(current_node.right, list)
+    return list
   end
-
   # Time Complexity: 
   # Space Complexity: 
-  def inorder
-    raise NotImplementedError
+  def inorder #return [] with order were given
+    list = []
+    return inorder_helper(@root, [])
   end
-
+  
+  # Root, Left, Right
+  def preorder_helper(current_node, list)
+    return list if current_node.nil?
+    list << { key: current_node.key, value: current_node.value }
+    preorder_helper(current_node.left, list)
+    preorder_helper(current_node.right, list)
+    return list
+  end
+  
   # Time Complexity: 
   # Space Complexity: 
   def preorder
-    raise NotImplementedError
+    list = []
+    return preorder_helper(@root, [])
+  end
+  
+  # 
+  
+  def postorder_helper(current_node, list)
+    return list if current_node.nil?
+    postorder_helper(current_node.left, list)
+    postorder_helper(current_node.right, list)
+    list << { key: current_node.key, value: current_node.value }
+    return list
   end
-
   # Time Complexity: 
   # Space Complexity: 
   def postorder
-    raise NotImplementedError
+    list = []  
+    return postorder_helper(@root, list)
   end
-
+  
+  
+  def height_helper(current_node)
+    return 0 if current_node.nil?
+    
+    left = height_helper(current_node.left)
+    right = height_helper(current_node.right)
+    
+    if left < right 
+      return right + 1
+    else
+      return left + 1
+    end
+    
+  end
+  
   # Time Complexity: 
   # Space Complexity: 
   def height
-    raise NotImplementedError
+    height = 0
+    return height_helper(@root)
   end
-
+  
   # Optional Method
   # Time Complexity: 
   # Space Complexity: 
   def bfs
     raise NotImplementedError
   end
-
+  
   # Useful for printing
   def to_s
     return "#{self.inorder}"