diff --git a/src/div.rs b/src/div.rs
index 693460b..718c3a1 100644
--- a/src/div.rs
+++ b/src/div.rs
@@ -8,44 +8,7 @@
 // Algorithm from [Daan Leijen. _Division and Modulus for Computer Scientists_,
 // December 2001](http://research.microsoft.com/pubs/151917/divmodnote-letter.pdf)
 
-use std::ops::{Add, Sub, Div, Rem};
-use std::num::{Zero, One};
-
-/// Same as `(a / b, a % b)`.
-#[inline]
-pub fn div_rem<T>(a: T, b: T) -> (T, T)
-        where T: Copy + Div<T,Output=T> + Rem<T,Output=T> {
-    (a / b, a % b)
-}
-
-/// Calculates a floored integer quotient.
-#[inline]
-pub fn div_floor<T>(a: T, b: T) -> T
-        where T: Copy + Ord + Zero + One +
-                 Add<T,Output=T> + Sub<T,Output=T> + Div<T,Output=T> + Rem<T,Output=T> {
-    div_mod_floor(a, b).0
-}
-
-/// Calculates a floored modulo.
-#[inline]
-pub fn mod_floor<T>(a: T, b: T) -> T
-        where T: Copy + Ord + Zero + One +
-                 Add<T,Output=T> + Sub<T,Output=T> + Div<T,Output=T> + Rem<T,Output=T> {
-    div_mod_floor(a, b).1
-}
-
-/// Calculates a floored integer quotient and modulo.
-#[inline]
-pub fn div_mod_floor<T>(a: T, b: T) -> (T, T)
-        where T: Copy + Ord + Zero + One +
-                 Add<T,Output=T> + Sub<T,Output=T> + Div<T,Output=T> + Rem<T,Output=T> {
-    let zero = Zero::zero();
-    let one = One::one();
-    match (a / b, a % b) {
-        (d, r) if (r > zero && b < zero) || (r < zero && b > zero) => (d - one, r + b),
-        (d, r)                                                     => (d, r),
-    }
-}
+pub use num::integer::{div_rem, div_floor, mod_floor, div_mod_floor};
 
 #[cfg(test)]
 mod tests {
diff --git a/src/lib.rs b/src/lib.rs
index 98f8ac1..82b32fd 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -267,7 +267,7 @@ Advanced time zone handling is not yet supported (but is planned in 0.3).
 
 #![doc(html_root_url = "https://lifthrasiir.github.io/rust-chrono/")]
 
-#![feature(std_misc, zero_one)] // lib stability features as per RFC #507
+#![feature(std_misc)] // lib stability features as per RFC #507
 #![cfg_attr(test, feature(test))] // ditto
 #![deny(missing_docs)]
 
@@ -600,7 +600,7 @@ pub trait Timelike {
 
 #[test]
 fn test_readme_doomsday() {
-    use std::iter::range_inclusive;
+    use num::iter::range_inclusive;
 
     for y in range_inclusive(naive::date::MIN.year(), naive::date::MAX.year()) {
         // even months
diff --git a/src/naive/date.rs b/src/naive/date.rs
index 6531fd9..6374d85 100644
--- a/src/naive/date.rs
+++ b/src/naive/date.rs
@@ -1495,7 +1495,7 @@ mod internals {
         use Weekday;
         use super::{Of, Mdf};
         use super::{YearFlags, A, B, C, D, E, F, G, AG, BA, CB, DC, ED, FE, GF};
-        use std::iter::range_inclusive;
+        use num::iter::range_inclusive;
         use std::u32;
 
         const NONLEAP_FLAGS: [YearFlags; 7] = [A, B, C, D, E, F, G];