diff --git a/src/number.rs b/src/number.rs
index 6b27fe2..1a29a99 100644
--- a/src/number.rs
+++ b/src/number.rs
@@ -16,6 +16,7 @@ use base::{TCFType, kCFAllocatorDefault};
 
 use libc::c_void;
 use std::mem;
+use std::num::{FromPrimitive, ToPrimitive};
 
 pub type CFNumberType = u32;