Try solving a few subtraction problems by using the complement method:
OCTAL NUMBER SYSTEM
The octal, or base 8, number system is a common system used with computers. Because of its
relationship with the binary system, it is useful in programming some types of computers.
Look closely at the comparison of binary and octal number systems in table 1-3. You can see that
one octal digit is the equivalent value of three binary digits. The following examples of the conversion of
octal 2258 to binary and back again further illustrate this comparison: