diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..7a60b85
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+__pycache__/
+*.pyc
diff --git a/src/__pycache__/calculator.cpython-315.pyc b/src/__pycache__/calculator.cpython-315.pyc
deleted file mode 100644
index 188bff0..0000000
Binary files a/src/__pycache__/calculator.cpython-315.pyc and /dev/null differ
diff --git a/src/calculator.py b/src/calculator.py
index 983e401..b6e95e6 100644
--- a/src/calculator.py
+++ b/src/calculator.py
@@ -8,11 +8,7 @@ def subtract(left: int, right: int) -> int:
     return left - right
 
 
-def multiply(left: int, right: int) -> int:
-    return left * right
-
-
-def divide(left: int, right: int) -> int:
+def modulo(left: int, right: int) -> int:
     if right == 0:
-        raise ValueError('division by zero')
-    return left // right
+        raise ValueError('modulo by zero')
+    return left % right