5. Computers are electronic machines that make accurate mathematical calculation [sums] at great speed they can complete in second calculations that would take people days to work out

7. These are the more common.They are the type used by people in business,scientists,and other people who want to do fast calculations.digital computers relate all problems two number,and produce their answers by counting numbers The simplest example of using a digital computers is counting on your fingers cash registers and adding machines are simple digital computers.Pocket calculators are small computers.They can do extremely difficult calculations at lightning speed

9. These work by hanging one quantity into another.a clock is a simple example.It changes time into movement.the clock tells you how much time has passed by showing you a corresponding amount of movement by the clock’s hands.A thermometer tells you the temperature by showing you the height of mercury in a tube.large analogue computers are often designed for search or for use in industry