Calculators
Number keys (0 to 9), arithmetic calculation keys (+ - ÷ ×), and functions keys such as memory are arranged on a square board, and the numbers and symbols entered and calculation results are shown on the screen at the top. Types are mainly ordinary calculators that perform arithmetic calculations and percentage calculations, function calculators that perform function calculations in scientific and engineering technical fields, and programmable calculators that can be programmed. Ordinary calculators include office calculators that can make office calculations quickly, and they are widely used. Function calculators can perform trigonometric functions as well as differentiation and integration, and they have many function keys enabling various function calculations. Many have functions such as those for statistics and rational number calculation. Programmable calculators are calculators that can perform complex calculations by program control, and they are also called pocket computers.