In general, number theory is notorious for containing many questions that are accessible to a layperson but whose proofs rely on arguments that are so difficult that even the basic idea of how the argument works takes many years of study.
Fermat's last theorem is an example, because it can be shown to be equivalent to, among other things, a very deep statement about elliptic curves (yep, the same thing The Fine Answer is about!) that Andrew Wiles proved.
Fermat's last theorem is an example, because it can be shown to be equivalent to, among other things, a very deep statement about elliptic curves (yep, the same thing The Fine Answer is about!) that Andrew Wiles proved.
https://en.wikipedia.org/wiki/Modularity_theorem