This library implements arbitrary-precision arithmetic on big integers
and on rationals.

This is a legacy library. It used to be part of the core OCaml
distribution (in otherlibs/num) but is now distributed separately. New
applications that need arbitrary-precision arithmetic should use the
Zarith library (https://github.com/ocaml/Zarith) instead of the Num
library, and older applications that already use Num are encouraged to
switch to Zarith. Zarith delivers much better performance than Num and
has a nicer API.