Appendix D. Binary and Hexadecimal Numbering

You weren’t expecting anything on the third R—’rithmatic—in this book, but Unicode uses hexadecimal references, as do several font utilities, and it helps to know the basics.

The number system we use is base 10. It has 10 different digits (0-9), and each “place” in a multi-digit number represents a power of 10, which increases by one as you move to the left. A digit represents how many of each power of 10 is included in the total. The number 256 is:

image

The computer is a binary animal, existing in a world of on/off, yes/no circuits and decisions. A binary numbering system has two different digits (0 and ...

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