There are two method finding of 2’s complement
(Most common method)
- Method – I

How to Find 2’s Complement by Method-I
Step -1: Take 1’s complement of each digit.(Opposite all the bits from 0 to 1 and 1 to 0 for making it in 1’s complement.
Step- 2: ADD one in the LSB(Least significant bit) as shown above in the diagram.
Step-3: Then it becomes in the form of 2’s complement.
(MOST TRICKY METHOD you never seen before)
- Method – II

How to Find 2’s Complement by Method-II
Step -1: Write all the digit the same as the given bit until found 1. When you see 1 in the given bit, write that 1.
Step -2 After founding 1, oppose all the bits from 1 to 0 and 0 to 1, for converting it into 2’s complement.
Step -3 Now, you can see the whole digit converted into 2’s complement.
One more example of Method- II

Operation with 2’s complement
- Case-1: Addition of two Positive value +5 and +2
- +5 Represents in binary ( 1 0 1 )
- +2 Represents in binary ( 0 1 0 )

Note – Computer is not understood – (negative) values so, for doing negative calculation the digit change into 2’s complement through the above method. If after calculation the result gives MSB bit 0 it denotes a positive value and if the result gives MSB bit 1 it means the value of the result is negative.
- Case-2: Subtraction of two value +5 and -2
- +5 Represents in binary (1 0 1 )
- +2 Represents in binary ( 0 1 0 )

- Convert +2 into -2 using 2’s complement
- -2 Represents in binary ( 1 1 0 )
- Case-3: Subtraction of two value -5 and -2
- -5 Represents in binary ( 0 1 1 )
- -2 Represents in binary ( 1 1 0 )
