The binary number system is just another way to represent numbers, like decimal, roman numerals, tick marks, etc. Most computers store and process numbers using binary. Decimal, which we all know and love, is base 10, while binary is base 2, which means that much of what we already know about working in decimal can be applied to working in binary with just a few simple changes. These links provide a few different introductions to the binary number system and how it is used in computers.