Why Friday the 13th is a mathematical inevitability
1659447091 Saturday, March 14, 2026
Summary
The article explains that Friday the 13th is a mathematical certainty, occurring because of the relationship between the Gregorian calendar and the number of days in a week. It examines the probability and frequency of this date, noting that it is not an irrational superstition but a predictable calendar phenomenon.
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Summary
scientificamerican.com