Source: /cirosantilli/simple-to-state-but-hard-to-prove

= Simple to state but hard to prove

One of the most beautiful things in mathematics are theorems of conjectures that are very simple to state and understand (e.g. for <K-12>, lower <undergrad> levels), but extremely hard to prove.

This is in contrast to conjectures in certain areas where you'd have to study for a few months just to precisely understand all the definitions and the interest of the problem statement.