A machine that performs tasks, such as mathematical calculations or electronic communication, under the control of a set of instructions called a program is a computer. Programs usually reside within and are retrieved and processed by 's electronics, and the program results are stored or routed to output devices, such as video display monitors or printers. Computers are used to perform a wide variety of activities with reliability, accuracy, and speed. Uses of Computers People use computers in a wide variety of ways. In business, computers tr ....