Binary subtractionis simplified as well, as long as we remember how subtraction and the base 2 number system. Let's first look at an easy example.

  111
 - 10
  101

Note that the difference is the same if this was decimal subtraction. Also similar to decimal subtraction is the concept of "borrowing". Watch as "borrowing" occurs when a larger digit, say 8, is subtracted from a smaller digit, say 5, as shown below in decimal subtraction.

    35
  -   8
    27

For 10 minus 1, 1 is borrowed from the "tens" column for use in the "ones" column, leaving the "tens" column with only 2. The following examples show "borrowing" in binary subtraction.

    10       100      1010
   -  1       - 10     - 110
      1          10       100