NIMCET 2016 Question Paper with solutions

${\left(1101\right)}_2-{\left(1010\right)}_2$
1 's complement of 1010 is 0101
Minued           $\mathit{–}1101$
1 's complement of subtrahend $\mathit{–}0101$
Carry over          $10010$
              ––––––
               $0011$
              ––––––
The required difference is 0011.