diff --git a/calculator.py b/calculator.py
index 89329a2..6c9be8b 100644
--- a/calculator.py
+++ b/calculator.py
@@ -1,11 +1,5 @@
-def add(a, b):
-    return a + b
-
-def subtract(a, b):
-    return a - b
-
-def multiply(a, b):
-    return a * b
-
-def divide(a, b):
-    return a / b
+def divide(a: int, b: int) -> float:
+    """Divides two numbers."""
+    if b == 0:
+        raise ZeroDivisionError("Cannot divide by zero")
+    return a / b
\ No newline at end of file
diff --git a/utils.py b/utils.py
index fd9ac00..3855792 100644
--- a/utils.py
+++ b/utils.py
@@ -1,5 +1,3 @@
-def greet(name):
-    return f"Hello, {name}"
-
-def is_even(n):
-    return n % 2 == 0
+def is_even(n: int) -> bool:
+    """Checks if a number is even."""
+    return n % 2 == 0
\ No newline at end of file