Tredici

Tredici is the Italian word for the number thirteen. It is the natural number that follows dodici and precedes quattordici. In numerals it is written as 13, and in Roman numerals as XIII.

Etymology: The form derives from Latin tredecim, from tre (three) and decem (ten). Through the evolution of Latin into the vernacular Italian, tredecim became tredici.

Mathematics: 13 is a prime number, the sixth prime, and it is also a Fibonacci number (the sequence 1, 1, 2, 3, 5, 8, 13, ...). As a two-digit numeral, it consists of the digits 1 and 3.

Usage and culture: In Italian, tredici is used in dates, ages, and counting. In various cultural contexts, including Italian-speaking communities, the number 13 is associated with a range of superstitions and interpretations, which vary by context and tradition.

Other contexts: In computing, the decimal value 13 corresponds to the carriage return control character in ASCII and Unicode. In calendrical systems, some lunisolar calendars designate a 13th month in leap years, as occurs in the Hebrew calendar. In other linguistic and cultural settings, tredici may appear in idioms, literature, and numerals used to indicate order, quantity, or time.

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