Here's a different (and IMHO quicker/easier) way to do it. First you'll need a chart comparing binary and hex values:

--------------------------------------
|   Binary   |   Hexadecimal   |
--------------------------------------
|    0000    |              0              |
|    0001    |              1              |
|    0010    |              2              |
|    0011    |              3              |
|    0100    |              4              |
|    0101    |              5              |
|    0110    |              6              |
|    0111    |              7              |
|    1000    |              8              |
|    1001    |              9              |
|    1010    |              A              |
|    1011    |              B              |
|    1100    |              C             |
|    1101    |              D             |
|    1110    |              E             |
|    1111    |              F              |
--------------------------------------

Ok, now, say you've got a binary number: 101100101100. Starting from right to left, divide the number into segments, each containing 4 numbers. Which will give you: 1011, 0010 and 1100. Then, look at the chart and find the hexadecimal values for each of those binary values:

---------------------------------
Binary               |  1011  |  0010  |  1100  |
---------------------------------
Hexadecimal  |     B      |     2      |     C     |
---------------------------------

Then, just remove the spaces inbetween the hexadecimal values, and voila!, you've got your hexadecimal equalvalent of the binary value you started with.

101100101100B = B2CH

I'd like to give a shout out to dann's E2 Offline Scratchpad for helping to make those charts.