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

  1. Aug 21, 2014 #1
    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
     
  2. jcsd
  3. Aug 21, 2014 #2

    rcgldr

    User Avatar
    Homework Helper

    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.
     
  4. Aug 22, 2014 #3

    Mark44

    Staff: Mentor

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