Two's complement: Am I on the right track here?

[Horizyn]

What is the the 2's complement representation of -14 using 5 bits?

1. (11110)2
2. (10100)2
3. (11001)2
4. (10010)2

I've changed to binary: 01110
Flipped over as in two's complement: 10010

So the likely answer seems to be option 4

Am I missing something?

Thanks

 

[rcgldr]

To take the negative of a number in two's complement, you can take the one's complement (invert all the bits), then increment by 1. In this case ~01110 = 10001, then increment by 1 = 10010. Negating again, ~10010 = 01101, then increment by 1 = 01110.

 

[Mark44]

As a check, if you add the binary representation of 14 to its two's complement representation, you should get 5 bits of 0.