diff --git a/current_age_for_birth_year.rb b/current_age_for_birth_year.rb
index e69de29..d9a373e 100644
--- a/current_age_for_birth_year.rb
+++ b/current_age_for_birth_year.rb
@@ -0,0 +1,3 @@
+def current_age_for_birth_year(birth_year)
+  2015 - birth_year
+end