we add that +1 because by complementing we make that number far from 1111...1 plus its original position also get shifted by 1 so by adding that 1 the result come to its actual position in the bit sequence for computation by the circuit implementation
we add that +1 because by complementing we make that number far from 1111...1 plus its original position also get shifted by 1 so by adding that 1 the result come to its actual position in the bit sequence for computation by the circuit implementation