Calculators are used to calculate numerals and equations, typically in mathematics or business.

The first mechanical calculator was invented by Blaise Pascal, a French mathematician, when he was 19 in 1642, to help is father calculate mathematic sums.

Calculators were originally gear driven wheels, but now they use a chip, typically a microchip, and some kind of energy source.

The first handheld calculator was invented by Texas Instruments, an American company, in 1967, and were further developed in the early 1970s.

School students are common users of calculators, using them to calculate difficult sums, although some say children are too dependent on the devices.

The display of numbers on a calculator are visible on an LCD (liquid-crystal display) screen, and are shown on the screen when a button is pressed.

Calculators are often powered with chemical or battery energy, solar energy or electrical energy.