diff --git a/lib/tree.rb b/lib/tree.rb
index c0d4b51..061a314 100644
--- a/lib/tree.rb
+++ b/lib/tree.rb
@@ -2,61 +2,157 @@ class TreeNode
   attr_reader :key, :value
   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
   attr_reader :root
+
   def initialize
     @root = nil
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: O(log(n))
+  # Space Complexity: O(1)
   def add(key, value)
-    raise NotImplementedError
+    new_node = TreeNode.new(key, value)
+
+    if @root.nil?
+      return @root = new_node
+    else
+      add_helper(@root, new_node)
+    end
+  end
+
+  def add_helper(current, new_node)
+    if current.nil?
+      return new_node
+    elsif new_node.key <= current.key
+      current.left = add_helper(current.left, new_node)
+    else
+      current.right = add_helper(current.right, new_node)
+    end
+    return current
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: O(log(n))
+  # Space Complexity: O(1)
   def find(key)
-    raise NotImplementedError
+    return nil if @root.nil?
+
+    current = @root
+    return find_helper(current, key)
+  end
+
+  def find_helper(root, key_to_find)
+    if root.nil?
+      return nil
+    elsif root.key == key_to_find
+      return root.value
+    elsif key_to_find < root.key
+      root.left = find_helper(root.left, key_to_find)
+    elsif key_to_find > root.key
+      root.right = find_helper(root.right, key_to_find)
+    end
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def inorder
-    raise NotImplementedError
+    inorder_array = []
+    current = @root
+
+    return inorder_array if current.nil?
+
+    return inorder_helper(current, inorder_array)
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  def inorder_helper(current, tree_array)
+    return tree_array if current.nil?
+
+    inorder_helper(current.left, tree_array)
+    tree_array.push({ :key => current.key,
+                     :value => current.value })
+    inorder_helper(current.right, tree_array)
+  end
+
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def preorder
-    raise NotImplementedError
+    preorder_array = []
+    current = @root
+
+    return preorder_array if current.nil?
+
+    return preorder_helper(current, preorder_array)
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  def preorder_helper(current, tree_array)
+    return tree_array if current.nil?
+
+    tree_array.push({ :key => current.key,
+                     :value => current.value })
+    preorder_helper(current.left, tree_array)
+    preorder_helper(current.right, tree_array)
+  end
+
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def postorder
-    raise NotImplementedError
+    postorder_array = []
+    current = @root
+
+    return postorder_array if current.nil?
+
+    return postorder_helper(current, postorder_array)
+  end
+
+  def postorder_helper(current, tree_array)
+    return tree_array if current.nil?
+
+    postorder_helper(current.left, tree_array)
+    postorder_helper(current.right, tree_array)
+    tree_array.push({ :key => current.key,
+                     :value => current.value })
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: O(n)
+  # Space Complexity:O(1)
   def height
-    raise NotImplementedError
+    current = @root
+
+    return 0 if current.nil?
+
+     height_helper(current)
+  end
+
+  def height_helper(current)
+    return 0 if current.nil?
+
+    right = height_helper(current.right)
+    left = height_helper(current.left)
+
+    if right > left
+      return right + 1
+    else
+      return left + 1
+    end
   end
 
   # Optional Method
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity:
+  # Space Complexity:
   def bfs
-    raise NotImplementedError
+    bfs_array = []
+    current = @root
+    return bfs_array if current.nil?
+    
+  # will come back to after queue exercises
   end
 
   # Useful for printing