diff --git a/spec/chapter1/lesson1.rb b/spec/exercises/chapter1/lesson1.rb
similarity index 86%
rename from spec/chapter1/lesson1.rb
rename to spec/exercises/chapter1/lesson1.rb
index 6562692..593b934 100644
--- a/spec/chapter1/lesson1.rb
+++ b/spec/exercises/chapter1/lesson1.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson1'
+require_relative '../../../src/exercises/chapter1/lesson1'
 
 RSpec.describe 'solution' do
   describe 'when n is 0' do
diff --git a/spec/chapter1/lesson10.rb b/spec/exercises/chapter1/lesson10.rb
similarity index 88%
rename from spec/chapter1/lesson10.rb
rename to spec/exercises/chapter1/lesson10.rb
index 2b98ab3..062072b 100644
--- a/spec/chapter1/lesson10.rb
+++ b/spec/exercises/chapter1/lesson10.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson10'
+require_relative '../../../src/exercises/chapter1/lesson10'
 
 RSpec.describe 'solution' do
   describe 'when x = 2, n = 3' do
diff --git a/spec/chapter1/lesson11.rb b/spec/exercises/chapter1/lesson11.rb
similarity index 86%
rename from spec/chapter1/lesson11.rb
rename to spec/exercises/chapter1/lesson11.rb
index 0e7bd23..d372f78 100644
--- a/spec/chapter1/lesson11.rb
+++ b/spec/exercises/chapter1/lesson11.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson11'
+require_relative '../../../src/exercises/chapter1/lesson11'
 
 describe 'solution' do
   context 'when n is 1' do
diff --git a/spec/chapter1/lesson12.rb b/spec/exercises/chapter1/lesson12.rb
similarity index 86%
rename from spec/chapter1/lesson12.rb
rename to spec/exercises/chapter1/lesson12.rb
index 414b6ea..cbc50f1 100644
--- a/spec/chapter1/lesson12.rb
+++ b/spec/exercises/chapter1/lesson12.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson12'
+require_relative '../../../src/exercises/chapter1/lesson12'
 
 describe 'solution' do
   context 'when n is 0' do
diff --git a/spec/chapter1/lesson13.rb b/spec/exercises/chapter1/lesson13.rb
similarity index 86%
rename from spec/chapter1/lesson13.rb
rename to spec/exercises/chapter1/lesson13.rb
index 8e4c9ce..ad287e4 100644
--- a/spec/chapter1/lesson13.rb
+++ b/spec/exercises/chapter1/lesson13.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson13'
+require_relative '../../../src/exercises/chapter1/lesson13'
 
 describe 'solution' do
   context 'when n is 0' do
diff --git a/spec/chapter1/lesson14.rb b/spec/exercises/chapter1/lesson14.rb
similarity index 86%
rename from spec/chapter1/lesson14.rb
rename to spec/exercises/chapter1/lesson14.rb
index 26ee2be..ca914f9 100644
--- a/spec/chapter1/lesson14.rb
+++ b/spec/exercises/chapter1/lesson14.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson14'
+require_relative '../../../src/exercises/chapter1/lesson14'
 
 describe 'solution' do
   context 'when n is 0' do
diff --git a/spec/chapter1/lesson15.rb b/spec/exercises/chapter1/lesson15.rb
similarity index 81%
rename from spec/chapter1/lesson15.rb
rename to spec/exercises/chapter1/lesson15.rb
index 005a657..b8e67c6 100644
--- a/spec/chapter1/lesson15.rb
+++ b/spec/exercises/chapter1/lesson15.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson15'
+require_relative '../../../src/exercises/chapter1/lesson15'
 
 describe 'solution' do
   it 'returns the correct result' do
diff --git a/spec/chapter1/lesson16.rb b/spec/exercises/chapter1/lesson16.rb
similarity index 94%
rename from spec/chapter1/lesson16.rb
rename to spec/exercises/chapter1/lesson16.rb
index eceb145..5473eea 100644
--- a/spec/chapter1/lesson16.rb
+++ b/spec/exercises/chapter1/lesson16.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson16'
+require_relative '../../../src/exercises/chapter1/lesson16'
 
 RSpec.describe 'solution' do
   it 'calculates the sum for n = 1 correctly' do
diff --git a/spec/chapter1/lesson2.rb b/spec/exercises/chapter1/lesson2.rb
similarity index 86%
rename from spec/chapter1/lesson2.rb
rename to spec/exercises/chapter1/lesson2.rb
index b622bcf..07f38d4 100644
--- a/spec/chapter1/lesson2.rb
+++ b/spec/exercises/chapter1/lesson2.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson2'
+require_relative '../../../src/exercises/chapter1/lesson2'
 
 RSpec.describe 'solution' do
   describe 'when n is 0' do
diff --git a/spec/chapter1/lesson3.rb b/spec/exercises/chapter1/lesson3.rb
similarity index 86%
rename from spec/chapter1/lesson3.rb
rename to spec/exercises/chapter1/lesson3.rb
index 05342c8..e241317 100644
--- a/spec/chapter1/lesson3.rb
+++ b/spec/exercises/chapter1/lesson3.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson3'
+require_relative '../../../src/exercises/chapter1/lesson3'
 
 RSpec.describe 'solution' do
   describe 'when n is 0' do
diff --git a/spec/chapter1/lesson4.rb b/spec/exercises/chapter1/lesson4.rb
similarity index 86%
rename from spec/chapter1/lesson4.rb
rename to spec/exercises/chapter1/lesson4.rb
index ebf1c57..72a5691 100644
--- a/spec/chapter1/lesson4.rb
+++ b/spec/exercises/chapter1/lesson4.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson4'
+require_relative '../../../src/exercises/chapter1/lesson4'
 
 RSpec.describe 'solution' do
   describe 'when n is 0' do
diff --git a/spec/chapter1/lesson5.rb b/spec/exercises/chapter1/lesson5.rb
similarity index 87%
rename from spec/chapter1/lesson5.rb
rename to spec/exercises/chapter1/lesson5.rb
index 35207ce..8ccec67 100644
--- a/spec/chapter1/lesson5.rb
+++ b/spec/exercises/chapter1/lesson5.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson5'
+require_relative '../../../src/exercises/chapter1/lesson5'
 
 RSpec.describe 'solution' do
   describe 'when n is 0' do
diff --git a/spec/chapter1/lesson6.rb b/spec/exercises/chapter1/lesson6.rb
similarity index 87%
rename from spec/chapter1/lesson6.rb
rename to spec/exercises/chapter1/lesson6.rb
index 403f927..2d92d3e 100644
--- a/spec/chapter1/lesson6.rb
+++ b/spec/exercises/chapter1/lesson6.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson6'
+require_relative '../../../src/exercises/chapter1/lesson6'
 
 RSpec.describe 'solution' do
   describe 'when n is 1' do
diff --git a/spec/chapter1/lesson7.rb b/spec/exercises/chapter1/lesson7.rb
similarity index 88%
rename from spec/chapter1/lesson7.rb
rename to spec/exercises/chapter1/lesson7.rb
index b3a31a9..c948628 100644
--- a/spec/chapter1/lesson7.rb
+++ b/spec/exercises/chapter1/lesson7.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson7'
+require_relative '../../../src/exercises/chapter1/lesson7'
 
 RSpec.describe 'solution' do
   describe 'when n is 2' do
diff --git a/spec/chapter1/lesson8.rb b/spec/exercises/chapter1/lesson8.rb
similarity index 88%
rename from spec/chapter1/lesson8.rb
rename to spec/exercises/chapter1/lesson8.rb
index a7cf513..c02f408 100644
--- a/spec/chapter1/lesson8.rb
+++ b/spec/exercises/chapter1/lesson8.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson8'
+require_relative '../../../src/exercises/chapter1/lesson8'
 
 RSpec.describe 'solution' do
   describe 'when n is 1' do
diff --git a/spec/chapter1/lesson9.rb b/spec/exercises/chapter1/lesson9.rb
similarity index 87%
rename from spec/chapter1/lesson9.rb
rename to spec/exercises/chapter1/lesson9.rb
index eb0e241..cdcf841 100644
--- a/spec/chapter1/lesson9.rb
+++ b/spec/exercises/chapter1/lesson9.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter1/lesson9'
+require_relative '../../../src/exercises/chapter1/lesson9'
 
 RSpec.describe 'solution' do
   describe 'when n is 1' do
diff --git a/spec/chapter2/lesson1.rb b/spec/exercises/chapter2/lesson1.rb
similarity index 92%
rename from spec/chapter2/lesson1.rb
rename to spec/exercises/chapter2/lesson1.rb
index 508f056..48d3984 100644
--- a/spec/chapter2/lesson1.rb
+++ b/spec/exercises/chapter2/lesson1.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter2/lesson1'
+require_relative '../../../src/exercises/chapter2/lesson1'
 
 RSpec.describe 'solution' do
   describe 'when all numbers are positive' do
diff --git a/spec/chapter2/lesson11.rb b/spec/exercises/chapter2/lesson11.rb
similarity index 92%
rename from spec/chapter2/lesson11.rb
rename to spec/exercises/chapter2/lesson11.rb
index 3d5f1e2..bcdb986 100644
--- a/spec/chapter2/lesson11.rb
+++ b/spec/exercises/chapter2/lesson11.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter2/lesson11'
+require_relative '../../../src/exercises/chapter2/lesson11'
 
 describe 'solution' do
   context 'when both numbers are prime' do
diff --git a/spec/chapter2/lesson2.rb b/spec/exercises/chapter2/lesson2.rb
similarity index 89%
rename from spec/chapter2/lesson2.rb
rename to spec/exercises/chapter2/lesson2.rb
index f7efd0a..f17254a 100644
--- a/spec/chapter2/lesson2.rb
+++ b/spec/exercises/chapter2/lesson2.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter2/lesson2'
+require_relative '../../../src/exercises/chapter2/lesson2'
 
 RSpec.describe 'solution' do
   describe 'when both numbers have the same sign' do
diff --git a/spec/chapter2/lesson3.rb b/spec/exercises/chapter2/lesson3.rb
similarity index 89%
rename from spec/chapter2/lesson3.rb
rename to spec/exercises/chapter2/lesson3.rb
index b1bec97..c9f88c5 100644
--- a/spec/chapter2/lesson3.rb
+++ b/spec/exercises/chapter2/lesson3.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter2/lesson3'
+require_relative '../../../src/exercises/chapter2/lesson3'
 
 RSpec.describe 'solution' do
   describe 'when a is 0' do
diff --git a/spec/chapter2/lesson4.rb b/spec/exercises/chapter2/lesson4.rb
similarity index 92%
rename from spec/chapter2/lesson4.rb
rename to spec/exercises/chapter2/lesson4.rb
index f83e565..21e6bd2 100644
--- a/spec/chapter2/lesson4.rb
+++ b/spec/exercises/chapter2/lesson4.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter2/lesson4'
+require_relative '../../../src/exercises/chapter2/lesson4'
 
 RSpec.describe 'solution' do
   describe 'when input is a valid month' do
diff --git a/spec/chapter2/lesson5.rb b/spec/exercises/chapter2/lesson5.rb
similarity index 86%
rename from spec/chapter2/lesson5.rb
rename to spec/exercises/chapter2/lesson5.rb
index 8b71b46..d3b8d72 100644
--- a/spec/chapter2/lesson5.rb
+++ b/spec/exercises/chapter2/lesson5.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter2/lesson5'
+require_relative '../../../src/exercises/chapter2/lesson5'
 
 RSpec.describe 'solution' do
   describe 'when n is 0' do
diff --git a/spec/chapter2/lesson6.rb b/spec/exercises/chapter2/lesson6.rb
similarity index 77%
rename from spec/chapter2/lesson6.rb
rename to spec/exercises/chapter2/lesson6.rb
index 26fd44f..660b723 100644
--- a/spec/chapter2/lesson6.rb
+++ b/spec/exercises/chapter2/lesson6.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter2/lesson6'
+require_relative '../../../src/exercises/chapter2/lesson6'
 
 RSpec.describe 'solution' do
   it 'returns the smallest integer n such that the sum of integers from 1 to n is greater than 10000' do
diff --git a/spec/chapter2/lesson8.rb b/spec/exercises/chapter2/lesson8.rb
similarity index 89%
rename from spec/chapter2/lesson8.rb
rename to spec/exercises/chapter2/lesson8.rb
index c6c003e..aac05a7 100644
--- a/spec/chapter2/lesson8.rb
+++ b/spec/exercises/chapter2/lesson8.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter2/lesson8'
+require_relative '../../../src/exercises/chapter2/lesson8'
 
 RSpec.describe 'solution' do
   describe 'when is n = 0' do
diff --git a/spec/chapter2/lesson9.rb b/spec/exercises/chapter2/lesson9.rb
similarity index 89%
rename from spec/chapter2/lesson9.rb
rename to spec/exercises/chapter2/lesson9.rb
index 75ad32f..2a34938 100644
--- a/spec/chapter2/lesson9.rb
+++ b/spec/exercises/chapter2/lesson9.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require_relative '../../src/exercises/chapter2/lesson9'
+require_relative '../../../src/exercises/chapter2/lesson9'
 
 RSpec.describe 'solution' do
   describe 'when n is 0' do
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
deleted file mode 100644
index b78b357..0000000
--- a/spec/spec_helper.rb
+++ /dev/null
@@ -1,24 +0,0 @@
-# spec/spec_helper.rb
-
-require 'simplecov'
-SimpleCov.start do
-  add_filter '/spec/' # Loại trừ thư mục spec khỏi báo cáo
-end
-
-RSpec.configure do |config|
-  config.expect_with :rspec do |expectations|
-    expectations.include_chain_clauses_in_custom_matcher_descriptions = true
-  end
-
-  config.mock_with :rspec do |mocks|
-    mocks.verify_partial_doubles = true
-  end
-
-  config.shared_context_metadata_behavior = :apply_to_host_groups
-
-  # Dừng test sau khi gặp lỗi đầu tiên
-  config.fail_fast = false
-
-  # Mặc định RSpec dùng random để sắp xếp các test
-  config.order = :random
-end