What is a Digit? Definition, Examples, and Number Systems

A digit is a symbol used to represent a numerical value in a number system. The most common number system is the decimal system, which uses ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. Other number systems, such as binary and hexadecimal, use a different number of digits to represent values. A digit's position in a number determines its value, with each position representing a multiple of the base of the number system. For example, in the number 123, the digit 1 represents 100, the digit 2 represents 20, and the digit 3 represents 3.