However, -0 still exists in 1's complement. It is 1111 in 4 bits, 11111111 in 8 bits, and all ones for any size bit pattern.

The nice thing about 1's complement is that a special subtraction circuit isn't needed. Instead, just add the negative of a number. We will not go through this process here because 1's complement is merely a stepping stone for 2's complement.

Virtually all modern computers use 2's complement to represent signed binary numbers internally. In the next section we will learn how to convert between 2's complement and decimal.