See also:

• Science: Math: Recreations: Famous Problems  (23)

• Millennium Prize Problems   - The seven problems proposed by the Clay Mathematics Institute: P versus NP; Hodge Conjecture; Poincaré Conjecture; Riemann Hypothesis; Yang-Mills Existence and Mass Gap; Navier-Stokes Existence and Smoothness; Birch and Swinnerton-Dyer Conjecture. Resources include articles on each problem by leading researchers.

• Mathematical Problems - In various subjects, compiled by Torsten Sillke.
• Most Wanted List - Elementary unsolved problems in mathematics, listed at the MathPages archive.
• Unsolved Problem of the Week Archive - A list of unsolved problems published by MathPro Press during 1995.