``` rust extern crate num; use num::rational::BigRational; fn main() { let x = from_str::<BigRational>("2/5").unwrap(); println!("{}, {}", x, x.round()); } ``` Prints "2/5, 1". The method is written here: http://static.rust-lang.org/doc/master/src/num/home/rustbuild/src/rust-buildbot/slave/nightly-linux/build/src/libnum/rational.rs.html#138-140 ``` rust pub fn round(&self) -> Ratio<T> { if *self < Zero::zero() { Ratio::from_integer((self.numer - self.denom + One::one()) / self.denom) } else { Ratio::from_integer((self.numer + self.denom - One::one()) / self.denom) } } ```