Final answer:
When subtracting an octet value from 256, we are essentially subtracting an 8-bit value from a 9-bit value. The result will be a 9-bit number.
Step-by-step explanation:
When subtracting an octet value from 256, we are essentially subtracting an 8-bit value (8 digits in binary) from a 9-bit value (256 in binary is 100000000). In binary, 256 - octet value would result in a 9-bit number. Here's an example: Let's say we subtract an octet value of 11001011. In binary, 256 is 100000000 and 11001011 is the octet value. Subtracting 11001011 from 100000000 gives us a 9-bit number, 001101011.