The world's unsolved problems
993 open questions across 14 fields, gathered from Wikipedia. Pick one and start thinking.
Showing all 993 problems · surprise me
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As the theory of Latin squares is a cornerstone in the design of experiments, solving the problems in Latin squares could have immediate…
As the theory of Latin squares is a cornerstone in the design of experiments, solving the problems in Latin squares could have immediate applicability to experimental design.
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Sampling of species problem
How is a probability updated when there is unanticipated new data?
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Doomsday argument
How valid is the probabilistic argument that claims to predict the future lifetime of the human race given only an estimate of the total number of humans born so far?
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Data last refreshed 2026-10-20 03:01 UTC.