Computers can be designed to do almost anything with information. Computers are used to control large and small machines which in the past were controlled by humans. They are also in homes, where they are used for things such as listening to music, reading the news and writing.

Modern computers are electronic computer hardware. They do mathematical arithmetic very quickly but computers do not really "think". They only follow the instructions in their software programs. The software uses the hardware when the user gives it instructions, and gives useful output.

Computer programs are designed or written by computer programmers. A few programmers write programs in the computer's own language called machine code. Most programs are written using a programming language like C++, Java, and Fortran. These programming languages are more like the language with which one talks and writes every day. The computer translates the user's instructions into binary code (machine code) that the computer will understand and do what is needed.