For those of us who can't keep all those numbers straight in our heads, here's a chart to help.

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|  256  |  128  |  64  |  32  |  16  |  8  |  4  |  2  |  1  |
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|           |           |         |        |         |      |      |       |       |
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The numbers in the top row are powers of 2, carried out to the eighth power. You can expand the chart if you need to, just double the previous number. Fill it in with the binary number you've got, say 010010110:

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|  256  |  128  |  64  |  32  |  16  |  8  |  4  |  2  |  1  |
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|    0     |    1    |    0   |   0   |   1   |  0  |   1  |  1 |  0   |
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In the binary numbering system the only numbers that you use are 0 and 1. If you have a 0 in a columb, then nothing exists there, if you have a 1, then you have 1 of whatever that columb is. (For example, if you have a 1 in the 64 columb, then you have 64). All you have to do to convert from binary to decimal is add up all the columbs that have a 1 in them. So...

2 + 4 + 16 + 128 = 150. Voila!

The E2 Offline Scratchpad rocks for making charts :)