sig
type t = { num : int; den : int; }
val add : Fractions.t -> Fractions.t -> Fractions.t
val sub : Fractions.t -> Fractions.t -> Fractions.t
val mult : Fractions.t -> Fractions.t -> Fractions.t
val inv : Fractions.t -> Fractions.t option
val div : Fractions.t -> Fractions.t -> Fractions.t option
val is_equal : Fractions.t -> Fractions.t -> bool
val of_int : int -> Fractions.t
val is_zero : Fractions.t -> bool
val one : Fractions.t
val zero : Fractions.t
end