diff --git a/README.md b/README.md
new file mode 100644
index 0000000..f6e6512
--- /dev/null
+++ b/README.md
@@ -0,0 +1,11 @@
+# learn-git
+Hello Class!
+
+## Slam
+
+<details>
+<summary>
+<code>package.json</code>
+test
+</summary>
+</details>
diff --git a/src/calc.py b/src/calc.py
index 2af3c17..d90b740 100644
--- a/src/calc.py
+++ b/src/calc.py
@@ -9,7 +9,7 @@ def add(a, b, third_operand = 0):
     """
     return a + b + third_operand
 
-def sub(a, b):
+def sub(a, b, third_arg =0):
     """
     Subtract some numbers
 
diff --git a/src/calc_test.py b/src/calc_test.py
index 2911910..e5d611d 100644
--- a/src/calc_test.py
+++ b/src/calc_test.py
@@ -17,6 +17,9 @@ def test_sub_2arg(self):
         # Make sure 4 - 3 = 1
         self.assertEqual(sub(4, 3), 1, 'subtracting three from four')
 
+    def test_sub_3arg(self):
+	self.assertEqual(sub(4, 3, 1), 0, 'subtracting three from four')
+
 
 if __name__ == '__main__':
     unittest.main()