A computer is a device that can be instructed to carry out an arbitrary set of arithmetic or logical operations automatically. The ability of computers to follow a sequence of operations, called a program, make computers very flexible and useful.

Computers are used as control systems for a wide variety of industrial and consumer devices, this includes simple special purpose devices like microwave ovens and remote controls, factory devices such as industrial robots and computer assisted design, but also in general purpose devices like personal computers and mobile devices such as smartphones.

The Internet is run on computers and it connects millions of other computers and their users.