"Explain how negative numbers are represented."
My answer is that if we ie. have the number 3 and want to convert that to -3 i do as follows: 3 = 0011 in 4 bits. i switch the 1s and 0s => 1100 and then add 1 => 1101, 1101 = -3.
Is this correct answer? and will that hold for 5,6,7... bits? Maybe someone can help me generalize it a bit more?