Weird Binary Conversion Questions

Discussion in 'Cisco' started by tman, Mar 3, 2008.

  1. tman

    tman Guest

    I have been studying for the CCNA test. I have been using the
    Trainsignal DVD which is very thorough. But when I tried some
    parctice tests at the Cisco website I got a couple of binary
    conversion questions that I did not understand. Can someone explain
    the meaning of these two questions.

    18. The decimal number 452 converted into a binary number, using
    successive division by 2, is _____.

    111000100
    110000100
    111001100
    101000100




    20. The binary number 11101000111 converted into a decimal number,
    using powers of 2, is _____.

    1183
    1873
    1638
    1863

    Thanks
    tman, Mar 3, 2008
    #1
    1. Advertising

  2. tman <> writes:
    >I have been studying for the CCNA test. I have been using the
    >Trainsignal DVD which is very thorough. But when I tried some
    >parctice tests at the Cisco website I got a couple of binary
    >conversion questions that I did not understand. Can someone explain
    >the meaning of these two questions.



    Its asking you to do a couple binary conversions. Since IP addresses
    and especially netmasks are numbers that can be expressed as binary
    numbers for ease of use to illustrate what is really going on, its is
    useful to know how to express decimal numbers as binary and back again.



    >18. The decimal number 452 converted into a binary number, using
    >successive division by 2, is _____.


    Its asking you to convert 452 to binary. There's generally two
    different ways you can do it by hand. Here's a website that outlines it.

    http://www.allaboutcircuits.com/vol_4/chpt_1/6.html


    >20. The binary number 11101000111 converted into a decimal number,
    >using powers of 2, is _____.


    Its asking you to convert 11101000111 to decimal. The same website
    probably has some page about this explicitly, but this is simpler to
    illustrate in a posting..

    1 * 2^0
    1 * 2^1
    1 * 2^2
    0 * 2^3
    0 * 2^4
    0 * 2^5
    1 * 2^6
    0 * 2^7
    1 * 2^8
    1 * 2^9
    1 * 2^10 +
    ===========

    Multiple it out, add it up, and it equals what?

    Again, they are just asking you to do the binary to decimal and back
    again by hand rather than by calculator (if yours supports it).
    Doug McIntyre, Mar 3, 2008
    #2
    1. Advertising

  3. tman

    tman Guest

    On Mar 3, 11:48 am, Doug McIntyre <> wrote:
    > tman <> writes:
    > >I have been studying for the CCNA test.  I have been using the
    > >Trainsignal DVD which is very thorough.  But when I tried some
    > >parctice tests at the Cisco website I got a couple of binary
    > >conversion questions that I did not understand.  Can someone explain
    > >the meaning of these two questions.

    >
    > Its asking you to do a couple binary conversions. Since IP addresses
    > and especially netmasks are numbers that can be expressed as binary
    > numbers for ease of use to illustrate what is really going on, its is
    > useful to know how to express decimal numbers as binary and back again.
    >
    > >18. The decimal number 452 converted into a binary number, using
    > >successive division by 2, is _____.

    >
    > Its asking you to convert 452 to binary. There's generally two
    > different ways you can do it by hand. Here's a website that outlines it.
    >
    > http://www.allaboutcircuits.com/vol_4/chpt_1/6.html
    >
    > >20. The binary number 11101000111 converted into a decimal number,
    > >using powers of 2, is _____.

    >
    > Its asking you to convert 11101000111 to decimal. The same website
    > probably has some page about this explicitly, but this is simpler to
    > illustrate in a posting..
    >
    > 1 * 2^0
    > 1 * 2^1
    > 1 * 2^2
    > 0 * 2^3
    > 0 * 2^4
    > 0 * 2^5
    > 1 * 2^6
    > 0 * 2^7
    > 1 * 2^8
    > 1 * 2^9
    > 1 * 2^10  +
    > ===========
    >
    > Multiple it out, add it up, and it equals what?
    >
    > Again, they are just asking you to do the binary to decimal and back
    > again by hand rather than by calculator (if yours supports it).


    Thanks Doug. i understand it now. My problem earlier was I did not
    understand the language e.g., powers of 2 and successive division by
    2. I had learned the "trial-and-fit" method.

    Thanks again for your help.
    tman, Mar 4, 2008
    #3
  4. In article
    <>,
    tman <> wrote:

    > I have been studying for the CCNA test.


    Isn't base conversion still taught in grade school? That's where I
    learned it about 35 years ago.

    But I'll bet most of you thought "I'll never need to use this in real
    life." :)

    --
    Barry Margolin,
    Arlington, MA
    *** PLEASE don't copy me on replies, I'll read them in the group ***
    Barry Margolin, Mar 4, 2008
    #4
  5. tman

    Guest

    On Mar 4, 6:53 am, Barry Margolin <> wrote:
    > In article
    > <>,
    >
    >  tman <> wrote:
    > > I have been studying for the CCNA test.

    >
    > Isn't base conversion still taught in grade school?  That's where I
    > learned it about 35 years ago.
    >
    > But I'll bet most of you thought "I'll never need to use this in real
    > life." :)
    >


    This is real life???

    Think yourself lucky, the window of opportunity
    is closing:)

    IPV6 will do away with it.

    Of course you need a slightly different conversion
    Hex-Binary but that of course is easy without
    requiring formal methods. I suppose formal methods may
    be needed in the initial learning stages.
    , Mar 4, 2008
    #5
  6. tman

    Guest

    I ran into this question too and could not figure it out but finaly I found a way to get to the right answer. I found it using this method.

    We all know that if we have 8 bits we use :

    128 64 32 16 8 4 2 1

    In this question we do not have 8 bits but we have 11 bits

    (11101000111)

    When you continue counting from bit 128 you will get this.

    1024 512 256 128 64 32 16 8 4 2 1

    Then if we add the bits which are enabled you get :


    1024 512 256 128 64 32 16 8 4 2 1
    1 1 1 0 1 0 0 0 1 1 1

    1024 + 512 + 256 + 64 + 4 + 2 + 1 = 1863










    Op maandag 3 maart 2008 18:58:38 UTC+1 schreef tman het volgende:
    > I have been studying for the CCNA test. I have been using the
    > Trainsignal DVD which is very thorough. But when I tried some
    > parctice tests at the Cisco website I got a couple of binary
    > conversion questions that I did not understand. Can someone explain
    > the meaning of these two questions.
    >
    > 18. The decimal number 452 converted into a binary number, using
    > successive division by 2, is _____.
    >
    > 111000100
    > 110000100
    > 111001100
    > 101000100
    >
    >
    >
    >
    > 20. The binary number 11101000111 converted into a decimal number,
    > using powers of 2, is _____.
    >
    > 1183
    > 1873
    > 1638
    > 1863
    >
    > Thanks
    , Aug 29, 2012
    #6
  7. tman

    Guest

    1024 512 256 128 64 32 16 8 4 2 1
    1 1 1 0 1 0 0 0 1 1 1






    Op maandag 3 maart 2008 18:58:38 UTC+1 schreef tman het volgende:
    > I have been studying for the CCNA test. I have been using the
    > Trainsignal DVD which is very thorough. But when I tried some
    > parctice tests at the Cisco website I got a couple of binary
    > conversion questions that I did not understand. Can someone explain
    > the meaning of these two questions.
    >
    > 18. The decimal number 452 converted into a binary number, using
    > successive division by 2, is _____.
    >
    > 111000100
    > 110000100
    > 111001100
    > 101000100
    >
    >
    >
    >
    > 20. The binary number 11101000111 converted into a decimal number,
    > using powers of 2, is _____.
    >
    > 1183
    > 1873
    > 1638
    > 1863
    >
    > Thanks
    , Aug 29, 2012
    #7
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Nocturnal
    Replies:
    45
    Views:
    2,240
  2. Al 2048

    Questions about conversion to DVD!!!

    Al 2048, Nov 5, 2003, in forum: DVD Video
    Replies:
    1
    Views:
    1,891
    MR_ED_of_Course
    Nov 5, 2003
  3. Patrick Michael

    Re: Questions....questions....questions

    Patrick Michael, Jun 16, 2004, in forum: A+ Certification
    Replies:
    0
    Views:
    787
    Patrick Michael
    Jun 16, 2004
  4. rajeswari01
    Replies:
    0
    Views:
    1,341
    rajeswari01
    Oct 15, 2010
  5. rajeswari01
    Replies:
    1
    Views:
    2,333
    julianm
    Jul 15, 2011
Loading...

Share This Page