### What fraction is closest to zero?

Fractions are infinitely dense and this means that between any two fractions there an infinite number of fractions. If any fraction, f, laid claims to being the nearest, there would be infinitely many fractions between 0 and f and so infinitely many fractions which were closer to 0. This means that f could not be the closest. The argument can be used again and again and so there cannot be a fraction closest to 0.