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I'm looking for a effective way to multiply Hexadecimal

For instance, i have to find value of the quadruple of 0.FEDC

0.FEDC * 4 = ???

Normally, i will have to change the hex to binary :

0.FEDC = 0000.11111110110111

Then convert the binary to decimal :

0000.11111110110111 = 0.99554443359375

And multiply the decimal :

0.99554443359375 * 4 = 3.982177734375

Then again, convert the multiplied value to binary :

3.982177734375 = 11.1111101101110000000000

And ... again, convert the binary

11.1111101101110000000000 = 3.FB7

Is there any other quicker ways than this ? Because when i take the exam i'm not allowed to use calculator or any kind of computer, and doing this manually is such a nightmare and time consuming

Any help is greatly appreciated !

NeedAnswers
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    Multiplying by a power of 2 is the same as a left-shift of all the bits. – vadim123 Aug 14 '14 at 14:19
  • @vadim123 if i change the hexa to decimal directly, it's gonna be too complicated for calculating. Like this : 0.15/16+14/256+13/4096+12/65536. Please correct me if i'm wrong, i'm very new to this !!! – NeedAnswers Aug 14 '14 at 14:30

1 Answers1

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You can just use the standard (decimal) multiplication techniques, with a larger multiplication table; all (positive, integer) bases work the same way, be it decimal, binary, or hexadecimal.

http://commons.wikimedia.org/wiki/File:Hexadecimal_multiplication_table.svg

FOr your example:

     4
0.FEDC
------
    30
   34
  38
3.C
------
3.FB70
Dan Uznanski
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