diff --git a/Math/PlusOne.swift b/Math/PlusOne.swift
index 709917a5..3e6eb27c 100644
--- a/Math/PlusOne.swift
+++ b/Math/PlusOne.swift
@@ -20,7 +20,7 @@ class PlusOne {
             index -= 1
         }
         
-        digits.insert(1, atIndex: 0)
+        digits.insert(1, at: 0)
         return digits
     }
-}
\ No newline at end of file
+}