This week's book giveaway is in the Game Development forum. We're giving away four copies of Badass: Making Users Awesome and have Kathy Sierra on-line! See this thread for details.

Consider a machine that performs calculations 4 bits at a time. Eight-bit 2's complement numbers can be added by adding the four least significant bits, followed by the four most significant bits. The leftmost bit is used for the sign, as usual. With 8 bits for each number, add -4 and -6, using 4-bit binary 2's complement arithmetic. Did overflow occur? Did carry occur? Verify your numeric result.