2s Complement
- Perform binary addition on the two numbers
- Ignore the carry out of the MSB
- Check for overflow
- Postive + Positive = Negative
- Negative + Negative = Positive
- A-B = A + (-B)
1s Complement
- Perform binary addition of the two number
- If there is a carry out of the MSB, add 1 to the result
- Check for overflow
- A - B = A + (-B)