Digits

Digits are symbols used to write numbers in a positional numeral system. In base-10, the digits are 0 through 9, and any number is formed by a sequence of these symbols. A single symbol such as 7 is a digit; a sequence like 314 represents a number when interpreted in a positional system.

The term digit refers to a single symbol, while a numeral is a string of digits that denotes a number. Digits are defined for a given base; other bases use different sets of digits. For example, hexadecimal uses digits 0–9 and the letters A–F as additional digits, and binary uses digits 0 and 1.

Digits are written and recognized across many writing systems. The Unicode standard encodes decimal digits for numerous scripts, such as the Devanagari digits ०–९, as well as digits used in Arabic, Thai, and other scripts. Some numeral systems, such as Roman numerals, are not positional digits and function differently from the Hindu-Arabic digit system.

History and usage: Hindu-Arabic numerals originated in India, introduced to the Islamic world, and eventually transmitted to Europe, where their place-value concept and the use of zero as a numeral and placeholder greatly facilitated arithmetic and mathematics.

In computing and digital technology, digits underpin data representation. Bits, the binary digits 0 and 1, form the fundamental units of information, while decimal digits are commonly used for human-readable output. Digit recognition and processing remain central to text handling, calculators, and numeric computations.