A display calculator is a device used to perform mathematical calculations. It typically consists of an LED display, a keyboard, and a memory. The LED display is used to show the results of calculations, while the keyboard is used to enter data and commands. The memory stores the data and instructions that are used in calculations. The most common type of display calculator is the ABACUS, which uses beads on rods to represent numbers. The ABACUS is a very simple and effective tool for performing basic calculations. Another type of display calculator is the CLEAR calculator, which uses a liquid crystal display (LCD) to show the results of calculations. This type of calculator is more advanced than the ABACUS and can be used to perform more complex calculations.