Subtraction of Two or Three 3-Digit Binary Numbers - JSS3 Mathematics Lesson Note

Binary subtraction uses the same principles as decimal subtraction, but with binary digits. The rules for binary subtraction are:

0−0=0

1−0=1

1−1=0

0−1=1 (borrow 1 from the next higher bit)

Example: Subtraction of Two 3-Digit Binary Numbers

Let's subtract 101 from 110.

    110

  - 101

  -----

    001

Step-by-step:

0−1 (borrow 1, becomes 10−1=1)

1−0=1

1−1=0

So, 110−101=001.

Example: Subtraction of Three 3-Digit Binary Numbers

Subtracting three binary numbers directly is a bit more complex. Let's subtract 

010 and 001 from 111.

First, subtract 

010 from 111:

    111

  - 010

  -----

    101

Then, subtract 001 from the result:

    101

  - 001

  -----

    100

So, 111−010−001=100.