Now let's consider how we would solve our problem of subtracting 110 from 710 using 2's complement.
 First, we need to convert 00012 to its negative equivalent in 2's complement. ``` 0111 (7) - 0001 - (1)``` To do this we change all the 1's to 0's and 0's to 1's and add one to the number. Notice that the most-significant digit is now 1 since the number is negative. ``` 0001 -> 1110 1 1111``` Next, we add the negative value we computed to 01112. This gives us a result of 101102. ``` 0111 (7) + 1111 +(-1) 10110 (?)``` Notice that our addition caused an overflow bit. Whenever we have an overflow bit in 2's complement, we discard the extra bit. This gives us a final answer of 01102 (or 610). ``` 0111 (7) - 0001 - (1) 0110 (6)```

The animation below demonstrates how to subtract the 5-bit binary numbers 011012 and 010012 using 2's complement representation. Click on the "Start Tutorial" button to view the animation.

Text-only version

Let's review the steps for subtracting x from y with an n-bit 2's complement representation.

1. Negate x using 2's complement.
1. Reverse all the bits in x.
2. Add 1 to form -x.