When you press a button on a calculator, electricity flows inside. Each button sends electricity to a different place. The circuits inside convert each number and symbol you enter into a language the calculator can understand. The calculator’s language, called machine language, uses the turning on and off of the switches to represent all numbers and symbols. This is because the calculator’s brain only knows two things. It knows when a switch is pressed (electricity is flowing) and when a switch is not pressed (electricity is not flowing). The calculator counts numbers by substituting 1 for on and 0 for off. That is the easiest way for electronic machines to solve problems. Inside the calculator, the turning on and off of switches is put together to make numbers. For example, the number 1 is “off, off, off, on” (0001) and the number 2 is “off, off, on, off” (0010). The number you enter is stored in a memory circuit. The calculator then waits for you to enter another number or an instruction, such as add (+), subtract (–), multiply (×), or divide (÷). When you press the “+” key, the calculator gets ready to add, and when you press the “–” key, it gets ready to subtract. Finally, when you press the equals (=) key, the electronic circuit for solving problems turns on and off over and over again at a very high speed to get your answer. It happens so fast that it seems to take no time at all! When the calculation is complete, the machine language made out of a long line of ones and zeros (on and off) passes through another circuit that turns it into normal numbers you can see on the LCD. Now, things might get a little more difficult from here on, as we learn how numbers are related to machine language. “Decimal and Binary” ← Click if you want to learn more!