diff --git a/add.py b/add.py
index d7dd2c4..247da70 100644
--- a/add.py
+++ b/add.py
@@ -1,3 +1,3 @@
 def add(a, b):
     """返回 a + b。"""
-    return abs(a) + abs(b)
+    return a+b
diff --git a/test_add.py b/test_add.py
index 3e51fb5..ee074bd 100644
--- a/test_add.py
+++ b/test_add.py
@@ -5,3 +5,6 @@ def test_add_positive():
 
 def test_add_zero():
     assert add(0, 5) == 5
+
+def test_add_with_negative():
+    assert add(-1, -2) == -3