diff --git a/__pycache__/calculator.cpython-39.pyc b/__pycache__/calculator.cpython-39.pyc
new file mode 100644
index 0000000..32ebaa5
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diff --git a/__pycache__/test_calculator.cpython-39.pyc b/__pycache__/test_calculator.cpython-39.pyc
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diff --git a/calculator.py b/calculator.py
index 306879a..6451dc5 100644
--- a/calculator.py
+++ b/calculator.py
@@ -1,3 +1,4 @@
+
 class Calculator:
     def add(self, a, b):
         return a + b
diff --git a/clear b/clear
new file mode 100644
index 0000000..0b4ca25
--- /dev/null
+++ b/clear
@@ -0,0 +1,65 @@
+commit a78cb6ab1c920e585c15f0fbfb8a83e90c206b6b (HEAD, origin/master, origin/HEAD)
+Author: alex2521-code <thanakrit.tae@mahidol.ac.th>
+Date:   Thu Nov 13 02:32:39 2025 +0000
+
+    Test commit 2
+
+commit 970f08e6de52b87bb7b0f4d1511c4dd1d37a73f1
+Author: alex2521-code <thanakrit.tae@mahidol.ac.th>
+Date:   Wed Nov 12 13:12:36 2025 +0000
+
+    show line error
+
+commit a8133f3433fbdb529a9870bbfba39298fa41b4ea
+Author: alex2521-code <thanakrit.tae@mahidol.ac.th>
+Date:   Wed Nov 12 13:11:02 2025 +0000
+
+    Added the test cases2
+
+commit 2e8dd5b2624fe65669825fc55f9afec4aa079453
+Author: alex2521-code <thanakrit.tae@mahidol.ac.th>
+Date:   Wed Nov 12 12:57:44 2025 +0000
+
+    Added the test cases by cmd
+
+commit 886c30470f3b7e3119639d7b9d5c4c56e14f6e81
+Author: Chaiyong Ragkhitwetsagul <cragkhit@gmail.com>
+Date:   Mon Nov 4 01:38:06 2024 +0000
+
+    Add one more bug
+
+commit af8f9360d321dff40108fb6d62d07c2ab51f4413
+Author: Chaiyong Ragkhitwetsagul <cragkhit@gmail.com>
+Date:   Sat Nov 2 23:14:44 2024 +0000
+
+    Updated the code
+
+commit 1d231767e3175bbb806dc6fef1047abc738a676a
+Author: Chaiyong Ragkhitwetsagul <cragkhit@gmail.com>
+Date:   Sat Nov 2 22:17:11 2024 +0000
+
+    Updated README.
+
+commit c03cd9084e4e23493d52139a2ebb6d460cb5f79f
+Author: Chaiyong Ragkhitwetsagul <cragkhit@gmail.com>
+Date:   Sat Nov 2 22:13:43 2024 +0000
+
+    Removed other test cases.
+
+commit cc20158fb48f090aa485de2cebde644737ab92bd
+Author: Chaiyong Ragkhitwetsagul <cragkhit@gmail.com>
+Date:   Sat Nov 2 22:12:24 2024 +0000
+
+    Added .gitignore
+
+commit 4eed8f1aa1c3268b010fa7716d68341a0e242f5b
+Author: Chaiyong Ragkhitwetsagul <cragkhit@gmail.com>
+Date:   Sat Nov 2 22:12:03 2024 +0000
+
+    Added initial files.
+
+commit 42aeda4c0e2092713331e5cb3ddaac55fb2f3db9
+Author: Chaiyong Ragkhitwetsagul <cragkhit@gmail.com>
+Date:   Sun Nov 3 05:04:11 2024 +0700
+
+    Initial commit
diff --git a/test_calculator.py b/test_calculator.py
index 7a241ca..5acc93f 100644
--- a/test_calculator.py
+++ b/test_calculator.py
@@ -1,15 +1,58 @@
+# import unittest
+# from calculator import Calculator
+
+# class TestCalculator(unittest.TestCase):
+
+#     def setUp(self):
+#         self.calc = Calculator()
+
+#     def test_add(self):
+#         self.assertEqual(self.calc.add(1, 2), 3)
+#         self.assertEqual(self.calc.add(-1, 5), 4)
+
+#     def test_subtract(self):
+#         # expected a - b
+#         self.assertEqual(self.calc.subtract(5, 3), -2)
+#         self.assertEqual(self.calc.subtract(3, 5), 2)
+#     # Add the following test methods to the TestCalculator class:
+
+# if __name__ == '__main__':
+#     unittest.main()
+
+
 import unittest
 from calculator import Calculator
 
 class TestCalculator(unittest.TestCase):
-
     def setUp(self):
         self.calc = Calculator()
 
     def test_add(self):
         self.assertEqual(self.calc.add(1, 2), 3)
+        self.assertEqual(self.calc.add(-1, 5), 4)
+
+    def test_subtract(self):
+        # expected a - b
+        self.assertEqual(self.calc.subtract(5, 3), 2)
+        self.assertEqual(self.calc.subtract(3, 5), -2)
+
+    def test_multiply(self):
+        self.assertEqual(self.calc.multiply(2, 3), 6)
+        self.assertEqual(self.calc.multiply(5, 0), 0)
+        self.assertEqual(self.calc.multiply(0, 5), 0)
+
+    def test_divide(self):
+        # integer division
+        self.assertEqual(self.calc.divide(10, 2), 5)
+        self.assertEqual(self.calc.divide(9, 2), 4)  # 9 // 2 == 4
+        self.assertEqual(self.calc.divide(0, 3), 0)
+        with self.assertRaises(ZeroDivisionError):
+            self.calc.divide(5, 0)
 
-    # Add the following test methods to the TestCalculator class:
+    # def test_modulo(self):
+    #     self.assertEqual(self.calc.modulo(10, 3), 1)
+    #     self.assertEqual(self.calc.modulo(9, 3), 0)
+    #     self.assertEqual(self.calc.modulo(2, 5), 2)
 
-if __name__ == '__main__':
-    unittest.main()
\ No newline at end of file
+if __name__ == "__main__":
+    unittest.main()