diff --git a/maths/binomial_coefficient.py b/maths/binomial_coefficient.py
index 0d4b3d1a8..6d5b46cb5 100644
--- a/maths/binomial_coefficient.py
+++ b/maths/binomial_coefficient.py
@@ -1,4 +1,4 @@
-def binomial_coefficient(n, r):
+def binomial_coefficient(n: int, r: int) -> int:
     """
     Find binomial coefficient using pascals triangle.