Solve the following using two's complement binary numbers: $ (-111)_{10}-(110)_{10}=?$
$(-111)_{10}=(10010001)_2$ with 2s complement
$-(110)_{10}=(10010010)_2$ with 2s complement
But $10010001+ 10010010 = 100100011$ which is $(291)_{10}$
Is this not the right way to add with two's complement?
You can check here that the values I got are correct: