What is the hardest math problem?
William Rodriguez
Published Jan 23, 2026
The longest-standing unresolved problem in the world was Fermat's Last Theorem, which remained unproven for 365 years. The “conjecture” (or proposal) was established by Pierre de Fermat in 1937, who famously wrote in the margin of his book that he had proof, but just didn't have the space to put in the detail.
Which is the hardest math problem in the world?
These Are the 10 Toughest Math Problems Ever Solved
- The Collatz Conjecture. Dave Linkletter. ...
- Goldbach's Conjecture Creative Commons. ...
- The Twin Prime Conjecture. ...
- The Riemann Hypothesis. ...
- The Birch and Swinnerton-Dyer Conjecture. ...
- The Kissing Number Problem. ...
- The Unknotting Problem. ...
- The Large Cardinal Project.