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October 7th, 2007, 08:01 PM  #1 
Senior Member Joined: Apr 2007 Posts: 2,140 Thanks: 0  I need some help on binary, hexadecimal and decimal numbers!
Okay, I was taking a look at my computer science textbook today, and I already did took a look at the equations for how to use binary and hexadecimal. But, I'm kind of confused on some of these. 1. Convert the following decimal numbers into hexadecimal and binary numbers: 100; 4340; 2000 2. Convert the following binary numbers into hexadecimal numbers and decimal numbers: 1000011001; 100000000; 100111 3. Convert the following hexadecimal numbers into binary and decimal numbers: FEFA9; 93; 2000 Can anyone tell me how to approach all the answers to these problems? Please show how to arrive to the answers. Thanks, J. 
October 8th, 2007, 06:19 AM  #2  
Global Moderator Joined: Nov 2006 From: UTC 5 Posts: 16,046 Thanks: 938 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms  Re: I need some help on binary, hexadecimal and decimal numb Quote:
1A7 = (0001)(1010)(0111) = 110100111 1111010 = (0111)(1010) = 7A To convert from decimal, divide by the base you convert to. The remainder becomes the rightmost digit; continue with the quotient until you have nothing left. 123 / 16 = 7 rm 11 Number so far: (11) = B 7 / 16 = 0 rm 7 Number so far: (7)(11) = 7B done. To convert to decimal, count the values at each place and multiply appropriately. Since binary only has 1s and 0s, just add the value of the position whenever you have 1s: 1010100 The last position is 1, the nexttolast is 2, and so on; in this example, the first position is 64. Here I label them vertically: 631 4268421 1010100 Since only 4, 16, and 64 are marked, I add 4 +16 + 64 = 84. With hexadecamal, the positions are 1, 16, 256, and so on. Just multiply at each step: 6AA = 6 * 256 + A * 16 + A = 6 * 256 + 10 * 16 + 10 = 1706.  
October 13th, 2007, 03:00 PM  #3 
Senior Member Joined: Apr 2007 Posts: 2,140 Thanks: 0 
Thanks for the help.


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