Proposed resolution:

The suggested wording changes are against the working draft N3242. Additional to the normative wording changes some editorial fixes are suggested.

1. In [time.duration.nonmember], change the following arithmetic function specifications as follows:

   template <class Rep1, class Period1, class Rep2, class Period2>
   constexpr typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>{>}::type
   operator+(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
   

   2 Returns: CD(lhs) += rhsCD(CD(lhs).count() + CD(rhs).count()).

   template <class Rep1, class Period1, class Rep2, class Period2>
   constexpr typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>{>}::type
   operator-(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
   

   3 Returns: CD(lhs) -= rhsCD(CD(lhs).count() - CD(rhs).count()).

   template <class Rep1, class Period, class Rep2>
   constexpr duration<typename common_type<Rep1, Rep2>::type, Period>
   operator*(const duration<Rep1, Period>& d, const Rep2& s);
   

   4 Remarks: This operator shall not participate in overload resolution unless Rep2 is implicitly convertible to CR(Rep1, Rep2).

   5 Returns: duration<CR(Rep1, Rep2), Period>(d) *= sCD(CD(d).count() * s).

   [...]

   template <class Rep1, class Period, class Rep2>
   constexpr duration<typename common_type<Rep1, Rep2>::type, Period>
   operator/(const duration<Rep1, Period>& d, const Rep2& s);
   

   8 Remarks: This operator shall not participate in overload resolution unless Rep2 is implicitly convertible to CR(Rep1, Rep2) and Rep2 is not an instantiation of duration.

   9 Returns: duration<CR(Rep1, Rep2), Period>(d) /= sCD(CD(d).count() / s).

   [...]

   template <class Rep1, class Period, class Rep2>
   constexpr duration<typename common_type<Rep1, Rep2>::type, Period>
   operator%(const duration<Rep1, Period>& d, const Rep2& s);
   

   11 Remarks: This operator shall not participate in overload resolution unless Rep2 is implicitly convertible to CR(Rep1, Rep2) and Rep2 is not an instantiation of duration.

   12 Returns: duration<CR(Rep1, Rep2), Period>(d) %= sCD(CD(d).count() % s)

   template <class Rep1, class Period1, class Rep2, class Period2>
   constexpr typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
   operator%(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
   

   13 Returns: common_type<duration<Rep1, Period1>, duration<Rep2, Period2> >::type(lhs) %= rhsCD(CD(lhs).count() % CD(rhs).count()).