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Computer Maths Help!

  • 18-08-2011 06:48PM
    #1
    James__10
    Registered Users, Registered Users 2 Posts: 1,526 ✭✭✭


    Was over on the maths forum but they didn't know how to solve these problems
    Number bases
    Q.Evaluate 101100111.011012 + 6C21.F616 giving your answer in base 8

    Q.Convert the following numbers to decimal:

    (i) 176.0158

    Is it just a case of mutiplying each of the numbers by a power? and powers are negative for the digits to the right of the decimal point?


Comments

  • #2
    FSL
    Registered Users, Registered Users 2 Posts: 1,456 ✭✭✭FSL


    Yes


  • #3
    Monotype
    Registered Users, Registered Users 2 Posts: 6,710 ✭✭✭Monotype


    I think it's like this...

    101100111.01101

    To base 10

    101100111

    (Going left) = 2^0 + 2^1 + 2^2 + 0^3 + 0^4 + 2^5 + 2^6 + 0^7 + 2^8 = 359

    .01101

    = 0/2 + 1/4 + 1/8 + 0/16 + 1/32

    (in other words 1/4 = 2^-2, 1/8 = 2^-3)



    It might be easier to just change to base 8 though.
    101100111
    Break up into blocks of 3 (this is blocks of 8 in binary)
    101-100-111
    5 - 4 - 7

    547 in base 8


    .01101
    (1/4 + 1/8 = 3 x 1/8) + (1/32 = 2 x 1/64)
    0.32

    Answer in base 8 = 547.32

    Then you need to figure out base 16 but I'm going to bed.

    6C21.F6
    In decimal,
    LHS is going to be 1 + 2x16 + 12x16x16 + 6x16x16x16
    RHS will be 15/16 + 6/(16x16) ---> You'd have to break it up as X/8 + X/64 + X/512 to convert to base 8.

    ... at least I think that's how it's done.


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