where do I get the answers?

In the binary number system their are two values (0 and 1). The smallest unit in binary is a bit which can be either a 0 or a 1. When you combine 8 bits together it is a byte. The binary numbering system is a positional numbering systems which means the position of the numbers indicate the relative value. Binary is a base 2 number system. The 8 positions in a byte are represented by the following values 128, 64, 32, 16, 8, 4, 2, 1. If the position in the byte is a 0 than it has no value and if its a 1 it has the value of its position. So the value in your question of: 00000011 = 3 because the first bit on the far left is 1 which has a positional value of 1 and the second bit is also a 1 and has a positional value of 2. So we add the bits together and 1 + 2 = 3.

 0    0    0    0   0   0   1   1
128  64   32   16   8   4   2   1

you can review the video at minute 140 (https://teamtreehouse.com/library/computer-basics/computer-basics/binary).