A computer is a machine that uses electronics to input, process, store, and output data. Data is information such as numbers, words, and lists. Input of data means to read information from a keyboard, a storage device like a hard drive, or a sensor. The computer processes or changes the data by following the instructions in software programs. A computer program is a list of instructions the computer has to perform. Programs usually perform mathematical calculations, modify data, or move it around. The data is then saved in a storage device, shown on a display, or sent to another computer. Computers can be connected together to form a network such as the internet, allowing the computers to communicate with each other.
The processor of a computer is made from integrated circuits (chips) that contains many transistors. Most computers are digital, which means that they represent information by using binary digits, or bits. Computers come in different shapes and sizes, depending on the brand and model and purpose. They range from small computers such as smartphones and laptops, to large computers such as supercomputers.