38 Chapter 2 Binary Values and Number Systems Binary, Octal, and Hexadecimal The base-2 (binary) number system is important in computing. It is also helpful to be familiar with number systems that are powers of 2, such as base 8 (octal), and base 16 (hexadecimal). Remember that the base value specifies the number of digits in the number system. Base 10 has ten digits (0–9), base 2 has two digits (0–1), and base 8 has eight digits (0–7). There-fore, the number 943 could not represent a value in any base less than base 10, because the digit 9 doesn’t exist in those bases. It is, however, a valid number in base 10 or any base higher than that. Likewise, the number 2074 is a valid number in base 8 or higher, but it simply does not exist (because it uses the digit 7) in any base lower than that. What are the digits in bases higher than 10? We need symbols to repre-sent the digits that correspond to the decimal values 10 and beyond. In bases higher than 10, we use letters as digits. We use the letter A to repre-
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