| Binary Subtraction |
|
| Just as with addition, we’re going to use the decimal numbering system to illustrate the process used in the binary numbering system for subtraction. |
|
| There are four possible cases of single-bit binary subtraction: 0 – 0, 0 – 1, 1 – 0, and 1 – 1. As long as the value being subtracted from (the minuend) is greater than or equal to the value subtracted from it (the subtrahend), the process is contained in a single column. |
|
Minuend – 0 1 1
Subtrahend -0 -0 -1
0 1 0 |
|
| But what happens in the one case when the minuend is less than the subtrahend? As in decimal, a borrow must be taken from the next most significant digit. The same is true for binary. |
|
|
|
|
| Pulling 1 from the next highest column in binary allows us to add 102 or a decimal 2 to the current column. For the previous example, 102 added to 0 gives us 102 or a decimal 2. When we subtract 1 from 2, the result is 1. |
|
|
|
