Why can't 00000100 = 3? Why does it have to be 00000011?

because 2^2 = 4

binary is base 2 and each space you move left it goes up one power.

0 0 1 1 1 = 2^2 + 2^1 + 2^0

0 0 4 2 1 = 4 + 2 + 1 = 7

Hi Kegan Windle

All internet "names" such as teamtreehouse.com are represented by an IPv4 or IPv6 address. In breaking down an address that is base 2, each octet is represented by 8 binary numbers, 0 or 1 (IPv6 is a bit more complex so I'll let you research if you're interested). Each 0 or 1 has a positional meaning that any device which understands routing can use to translate IP to name. To convert base 2 to base 10 the following math is required:

Each octet (dotted notation, so x.x.x.x for IPv4) contains a 0 or 1 and begins with the last binary number in the octet. So

X X X X X X X X X 192 128 64 32 16 8 4 2 1

Start from right to left and if there is a 1 in that position then it is considered 'on' and you would add that number to any other number containing a 1, anything with a 0 is considered 'off' and you do not add that number. Remember to only work with one octet at a time for simplicity sake. Here is one of the main websites I used throughout my career as a Network Administrator.

https://www.subnetting.net/Tutorial.aspx

Take care!