diff --git a/lib/recursive-methods.rb b/lib/recursive-methods.rb
index fbf6faa..2402447 100644
--- a/lib/recursive-methods.rb
+++ b/lib/recursive-methods.rb
@@ -1,49 +1,110 @@
 # Authoring recursive algorithms. Add comments including time and space complexity for each method.
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n)
+# Space complexity: O(n)
 def factorial(n)
-    raise NotImplementedError, "Method not implemented"
+  if n < 0
+    raise ArgumentError
+  end
+  return 1 if n == 1 || n == 0
+  return n * factorial(n-1)
 end
 
-# Time complexity: ?
-# Space complexity: ?
-def reverse(s)
-    raise NotImplementedError, "Method not implemented"
+# Time complexity: 0(n)
+# Space complexity: 0(n)
+def reverse(s, i = 0, j = -1, n_s = "")
+  if i == s.length
+  else
+    n_s << s[j]
+    reverse(s, i + 1, j -1, n_s)
+  end
+  return n_s
 end
 
-# Time complexity: ?
-# Space complexity: ?
-def reverse_inplace(s)
-    raise NotImplementedError, "Method not implemented"
+# Time complexity: 0(n)
+# Space complexity: 0(n)
+def reverse_inplace(s, i = 0, j = -1)
+  if i == s.length/2
+  else
+    temp = s[i]
+    s[i] = s[j]
+    s[j] = temp
+    reverse_inplace(s, i + 1, j - 1)
+  end
+  return s
 end
 
-# Time complexity: ?
-# Space complexity: ?
-def bunny(n)
-    raise NotImplementedError, "Method not implemented"
+# Time complexity: O(n)
+# Space complexity: O(n)
+def bunny(n, i = 0, j = 0)
+  if n == i
+    return j
+  else
+    return bunny(n, i + 1, j + 2)
+  end
 end
 
-# Time complexity: ?
-# Space complexity: ?
-def nested(s)
-    raise NotImplementedError, "Method not implemented"
+# Time complexity: O(n)
+# Space complexity: O(n)
+def nested(s, i = 0, ope = 0, close = 0)
+  return false if s.length % 2 != 0
+  if i < s.length
+    if s[i] == "("
+      ope += 1
+    else
+      if i >= 1
+        close += 1
+      else
+        return false
+      end
+    end
+    return nested(s, i + 1, ope, close)
+  end
+  return ope == close
 end
 
-# Time complexity: ?
-# Space complexity: ?
-def search(array, value)
-    raise NotImplementedError, "Method not implemented"
+# Time complexity: O(n)
+# Space complexity: O(n)
+def search(array, value, i = 0)
+  return false if array.length == 0
+  if array[i] == value
+    return true
+  end
+  if i < array.length
+    return search(array, value, i + 1)
+  else
+    return false
+  end
 end
 
-# Time complexity: ?
-# Space complexity: ?
-def is_palindrome(s)
-    raise NotImplementedError, "Method not implemented"
+# Time complexity: O(n)
+# Space complexity: O(n)
+def is_palindrome(s, i = 0, j = -1, coun = 1)
+  return true if s == ""
+  if i < s.length / 2
+    if s[i] == s[j]
+      return is_palindrome(s, i + 1, j - 1, coun + 1)
+    else
+      return false
+    end
+  end
+  return coun % 2 == 0
 end
 
-# Time complexity: ?
-# Space complexity: ?
-def digit_match(n, m)
-    raise NotImplementedError, "Method not implemented"
+# Time complexity:  O(n)
+# Space complexity: O(n)
+def digit_match(n, m, i = 0, coun = 0)
+  if (n.class != Array) && (m.class != Array)
+    n = n.digits
+    m = m.digits
+  end
+  if i < n.length
+    if n[i] == m[i]
+      return digit_match(n, m, i + 1, coun + 1)
+    else 
+      return digit_match(n, m, i + 1, coun)
+    end
+  else
+    return coun
+  end
 end
\ No newline at end of file
diff --git a/test/recursion_writing_test.rb b/test/recursion_writing_test.rb
index 820810e..ea9d002 100644
--- a/test/recursion_writing_test.rb
+++ b/test/recursion_writing_test.rb
@@ -38,7 +38,7 @@
   end
 end
 
-xdescribe "reverse" do
+describe "reverse" do
   it "will reverse 'cat'" do
     # Arrange
     string = "cat"
@@ -84,7 +84,7 @@
 end
 
 
-xdescribe "reverse_in_place" do
+describe "reverse_in_place" do
   it "will reverse 'cat'" do
     # Arrange
     string = "cat"
@@ -129,7 +129,7 @@
   end
 end
 
-xdescribe "bunny" do
+describe "bunny" do
   it "returns 0 for 0 bunnies" do
     # Arrange
     count = 0
@@ -164,7 +164,7 @@
   end
 end
 
-xdescribe "nested" do
+describe "nested" do
   it "will return true for empystring" do
     # Arrange
     string = ""
@@ -210,7 +210,7 @@
   end
 end
 
-xdescribe "search" do
+describe "search" do
   it "will return false for empty array" do
     # Arrange
     item = "a"
@@ -260,7 +260,7 @@
     end      
 end
 
-xdescribe "is_palindrome" do
+describe "is_palindrome" do
   it "will return true for emptystring" do
     # Arrange
     string = ""
@@ -295,7 +295,7 @@
   end
 end
 
-xdescribe "digit_match" do
+describe "digit_match" do
   it "returns 4 for 1072503891 and 62530841" do
     # Arrange
     num1 = 1072503891
@@ -304,8 +304,8 @@
     # Act
     answer = digit_match(num1, num2)
 
-     # Assert
-     expect(answer).must_equal 4
+    # Assert
+    expect(answer).must_equal 4
   end
 
   it "returns 0 for nonmatching numbers" do
@@ -316,8 +316,8 @@
     # Act
     answer = digit_match(num1, num2)
 
-     # Assert
-     expect(answer).must_equal 0
+    # Assert
+    expect(answer).must_equal 0
   end
 
   it "returns 3 for 841 and 62530841" do
@@ -328,8 +328,8 @@
     # Act
     answer = digit_match(num1, num2)
 
-     # Assert
-     expect(answer).must_equal 3
+    # Assert
+    expect(answer).must_equal 3
   end
   
   it "returns 1 for (0, 0)" do
@@ -340,8 +340,8 @@
     # Act
     answer = digit_match(num1, num2)
 
-     # Assert
-     expect(answer).must_equal 1
+    # Assert
+    expect(answer).must_equal 1
   end
   
   it "returns 1 for (10, 20)" do
@@ -352,7 +352,7 @@
     # Act
     answer = digit_match(num1, num2)
 
-     # Assert
-     expect(answer).must_equal 1
+    # Assert
+    expect(answer).must_equal 1
   end
 end