Inside of a Calculator

The insides of a calculator are actually very interesting. Well um..... OK I guess. You see it has a few different parts. It has a power source, rubber keys, circuit board, motherboard, and screen. Each thing has an important purpose. This is basically how it works:

1.  Someone presses the keys, cause the rubber to come in contact with the circuit board
2. The circuit board gives the motherboard information on the users input
3. The motherboard does the operation
4. The answer is shown on the screen

This is basic. Here is a real explanation: http://www.explainthatstuff.com/calculators.html