diff --git a/lib/tree.rb b/lib/tree.rb
index c0d4b51..bb8d2ba 100644
--- a/lib/tree.rb
+++ b/lib/tree.rb
@@ -16,47 +16,149 @@ def initialize
     @root = nil
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: O(log n) 
+  # Space Complexity: 0(1)
   def add(key, value)
-    raise NotImplementedError
+    if @root.nil?
+      @root = TreeNode.new(key, value)
+      return
+    end
+
+    current_node = @root
+
+    while current_node != nil
+      if current_node.key < key 
+        if current_node.right == nil
+          current_node.right = TreeNode.new(key, value)
+          return
+        end
+        current_node = current_node.right 
+      else 
+        if current_node.left == nil
+          current_node.left = TreeNode.new(key, value)
+          return 
+        end
+        current_node = current_node.left
+      end
+    end
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: O(log n)
+  # Space Complexity: 0(1)
   def find(key)
-    raise NotImplementedError
+    if @root.nil?
+      return nil
+    end
+
+    current_node = @root
+
+    while current_node != nil
+      if current_node.key == key
+        return current_node.value
+      elsif current_node.key < key
+        current_node = current_node.right
+      elsif current_node.key > key
+        current_node = current_node.left
+      end
+    end
+    print "No value found"
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: 0(n)
+  # Space Complexity: 0(n) 
   def inorder
-    raise NotImplementedError
+    if @root.nil?
+      return []
+    end
+    return inorder_helper(@root, [])
   end
+  
+  def inorder_helper(current_node, array)
+    if current_node.nil?
+      return array
+    end
 
-  # Time Complexity: 
-  # Space Complexity: 
+    inorder_helper(current_node.left, array) if current_node.left
+    array << {key: current_node.key, value: current_node.value}
+    inorder_helper(current_node.right, array) if current_node.right
+    
+    return array
+  end
+
+  # Time Complexity: 0(n)
+  # Space Complexity: 0(n)
   def preorder
-    raise NotImplementedError
+    if @root.nil?
+      return []
+    else
+      return preorder_helper(@root, [])
+    end
+  end
+  
+  def preorder_helper(current_node, array)
+    if current_node.nil?
+      return array
+    end
+    
+    array << {key: current_node.key, value: current_node.value}
+    preorder_helper(current_node.left, array)
+    preorder_helper(current_node.right, array)
+    
+    return array
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: 0(n)
+  # Space Complexity: 0(n)
   def postorder
-    raise NotImplementedError
+    if @root == nil
+      return []
+    else
+      return postorder_helper(@root, [])
+    end
+  end
+  
+  def postorder_helper(current_node, array)
+    if current_node.nil?
+      return array
+    end
+    
+    postorder_helper(current_node.left, array)
+    postorder_helper(current_node.right, array)
+    array.push({key: current_node.key, value: current_node.value})
+    
+    return array
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: 0(n)
+  # Space Complexity: 0(n)
   def height
-    raise NotImplementedError
+    if @root.nil?
+      return 0
+    elsif @root.left.nil? && @root.right.nil?
+      return 1
+    end
+    return height_helper(@root)
+  end
+  
+  def height_helper(current_node)
+    if current_node.nil?
+      return 0
+    end
+    
+    left = height_helper(current_node.left)
+    right = height_helper(current_node.right)
+    if left > right
+      return left + 1
+    else
+      return right + 1
+    end
   end
 
   # Optional Method
   # Time Complexity: 
   # Space Complexity: 
   def bfs
-    raise NotImplementedError
+
   end
 
   # Useful for printing