Head First HTML with CSS

Step two:
Convert each hex number into its decimal equivalent.
Now that you have the components separated you can compute the value for
each from 0 to 255. Let’s start with the hex number for the red component:
Now take the left-most
number and convert it to
its decimal value, and also
multiply it by 16.
CC
12
Take the right-most
number and write down
its decimal value.
12 * 16 = 192
Finally, add these two
numbers together. 192 + 12 = 204
Step three:
Now do this for the other two values.
Repeat the same method on the other two values. Here’s what you should get:
Step four:
CC 66 00
204 102 0
There is no step four, you’re done!
That’s it. Now you’ve got the numbers for each component and you know
exactly how much red, green, and blue go into the color. You can disassemble
any hex color in exactly the same way. Now let’s see how you’ll usually
determine Web colors.
styling with fonts and colors
So 204 is the decimal
equivalent of CC in hex.
To calculate 66, you have
(6 * 16) + 6 = 102
To calculate 00, you have
(0 * 16) + 0 = 0
you are here 371