Binary numbers are a system of counting that uses only two digits: 0 and 1. This base-2 numeral system is fundamental in computer science because it aligns with the way computers process data using electrical signals, which can be either off (0) or on (1). Each digit in a binary number represents a power of 2, making it possible to represent any number using combinations of these two digits. In binary, the number 10 represents the decimal number 2, while 11 represents 3. To convert a binary number to decimal, you multiply each digit by 2 raised to the power of its position, starting from 0 on the right. This system is essential for programming and digital electronics, as it forms the basis for data representation and processing in modern technology.