Computers make use of the binary system (i.e. they store data in binary format and also perform calculations in binary format). The binary system has just two numbers; 1 and 0 which correspond to two possible states of something , “on" and “off". This directly corresponds to there either being an electrical current present, or said electrical current being absent. The “on" state is assigned the value “1”, while the “off" state is assigned the value “0".