Arithmetic with Signed Numbers

Arithmetic with two’s complement

A powerful aspect of two’s complement representation is the ease with which we can carry out addition and subtraction.

The decimal property $a - b = a + (-b)$ can essentially be extended to two’s complement as well.

This means that the computer can use the same tools for two’s complement subtraction as it does for addition. One’s complement subtraction on the other hand requires complex circuitry.

Let’s go through an example of addition and an example of subtraction.