Let's take a quick review of all that we have learned about number systems.

- We began by introducing
the binary number system and discussing the importance of binary
numbers to computers. We learned that the binary number system is the
language which the computer understands.

- We began learning how to speak the binary language by comparing it
with a language we already understand: the decimal system. We learned
how to convert
between binary and decimal, how to perform
binary arithmetic, and how to represent
signed numbers. We discovered that we can perform all of our arithmetic
operations using only addition and a special representation for signed
numbers. This fact allows computer engineers to simplify the design
of computer processors.

- We examined two other number systems: octal and hexadecimal. These number systems have a special relationship to the binary system because their bases are powers of 2. This relationship makes conversion from binary to octal or hexadecimal and vice versa quite simple. For this reason, octal and hexadecimal are often used as a shorthand for writing long binary numbers.