diff --git a/.github/workflow/python_test.yml b/.github/workflows/python_test.yml
similarity index 88%
rename from .github/workflow/python_test.yml
rename to .github/workflows/python_test.yml
index 4121e1c..581a46c 100644
--- a/.github/workflow/python_test.yml
+++ b/.github/workflows/python_test.yml
@@ -18,4 +18,4 @@ jobs:
         python-version: 3.8
     - name: Run tests
       run: |
-        pytthon -m unittest test_main.py -v
+        python -m unittest test_main.py -v
diff --git a/main.py b/main.py
index 8d0b480..7af49ee 100644
--- a/main.py
+++ b/main.py
@@ -2,7 +2,7 @@ class Calculator:
     """A simple calculator with basic arithmetic operations."""
 
     def add(self, a, b):
-        return a + b
+        return a - b
 
     def subtract(self, a, b):
         return a - b