Two is the base of the simplest system of numbers in which natural numbers can be written concisely , being the length of the number a logarithm of the value of the number ( whereas in base 1 the length of the number is the value of the number itself ) ; the binary system is used in computers . Two is the base of the simplest numeral system in which natural numbers can be written concisely , being the length of the number a logarithm of the value of the number ( whereas in base 1 the length of the number is the value of the number itself ) ; the binary system is used in computers .