diff --git a/src/calc_test.py b/src/calc_test.py
index 2911910..1ce97af 100644
--- a/src/calc_test.py
+++ b/src/calc_test.py
@@ -8,7 +8,7 @@ def test_add_2arg(self):
         self.assertEqual(add(3, 4), 7, 'adding three and four')
 
     def test_add_3arg(self):
-        self.assertEqual(add(3, 5, 2), 10, 'adding three, five and two')
+        self.assertEqual(add(5, 3, 2), 10, 'adding three, five and two')
 
     def test_add_zeroes(self):
         self.assertEqual(add(0, 0, 0), 0 , 'adding zeroes together is zero')
@@ -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):
+        # Make sure 4 - 3 = 1
+        self.assertEqual(sub(4, 3, 1), 0, 'subtracting three from four')
 
 if __name__ == '__main__':
     unittest.main()