Base-2 representation, also known as binary, is a numerical system that uses only two digits: 0 and 1. Each digit's position represents a power of 2, starting from the rightmost digit, which is 2^0. This system is fundamental in computing, as it aligns with the on-off states of electronic circuits. In binary, the number 10 represents the decimal number 2, while 11 represents 3. To convert a binary number to decimal, you sum the values of the positions where there is a 1. For example, the binary number 101 equals 1*2^2 + 0*2^1 + 1*2^0, which equals 5 in decimal.