The maths account with no workingSourced
Correct answers, almost no steps.
The mystery lasted about a decade.
An account called Cleo posted 39 answers to difficult integrals on a mathematics forum between 2013 and 2015, usually without showing the working. People debated who was behind it until software developer Vladimir Reshetnikov identified himself as Cleo in 2025.
The mystery outlasted
the calculations.
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Cleo (mathematician) · Wikimedia contributors
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Reviewed: 2026-10-01