How do calculators work?

Pressing a key closes a circuit in a grid under the keypad, telling the chip which button was pushed. The chip stores numbers in binary, a code of only 1s and 0s, often using a form called binary-coded decimal. Circuits called adders combine logic gates to add binary digits, and multiplication and division are done through repeated adding, subtracting and shifting. Functions such as sine and square roots are worked out with clever step-by-step methods like the CORDIC algorithm. The result is then shown on a liquid crystal display, usually built from seven-segment digits.