Simple calculators perform only the basic four functions of addition, subtraction, multiplication, and division. More sophisticated calculators can perform trigonometric, statistical, logarithmic, and other advanced calculations. Some electronic calculators are actually small computers with limited memory and programming capabilities. Others are also available that include nonmathematical functions such as data storage and schedule organizing. The personal digital assistant, a hand-held device optimized as an organizer with communications capability and accepting handwritten input, is a bridge from calculators to full computer function.
Some calculators use an LCD readout to provide a graphic, as well as numeric, display.
Some calculators are powered by solar cells in ordinary room light.