diff --git a/app/app/calc.py b/app/app/calc.py
new file mode 100644
index 0000000..6367cfc
--- /dev/null
+++ b/app/app/calc.py
@@ -0,0 +1,6 @@
+"""
+Calculator functions
+"""
+
+def add(x, y):
+    return x + y
diff --git a/app/app/tests.py b/app/app/tests.py
new file mode 100644
index 0000000..6ac392a
--- /dev/null
+++ b/app/app/tests.py
@@ -0,0 +1,14 @@
+"""
+Sample tests
+"""
+
+from django.test import SimpleTestCase
+
+from app import calc
+
+class CalcTests(SimpleTestCase):
+    
+    def test_add_numbers(self):
+        res = calc.add(5, 6)
+
+        self.assertEqual(res, 11)