The easiest way to understand binary is like this: the very rightmost number is worth 1, and then to the left of that, you multiply 1 by 2, that place is worth 2, etc
11 = 3
10 = 2
01 = -1 ( I think)
so think of it like this, take 1, and every number to the left of it, you multiply it by 2 every time, so you go 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, etc. Every number to the right of the one you're looking at is ALWAYS worth 1 value less than what you're looking at. I know I'm bad at explaining this, but it's how I understand it, so if you're looking at 10000, which is equal to 32, then the "0000" is 1+2+4+8+16, even though 0 represents off and 1 represents on.
I just realized this thread is a month old, but my post is educational, so gtfo and don't call me on a necro.