Today, calculators are everywhere. Many kids probably take them for granted. After all, any smartphone will have a calculator application right there on the home screen. You can also go to any discount store and pick up a basic solar-powered calculator for a dollar or two. If you have a computer, you have all the calculating power you need at your fingertips.
Although calculators are very common today, they weren’t always cheap and easily accessible. In fact, they didn’t really come around until the dawn of the computer age. Before that time, you had to rely upon pencil and paper or, perhaps, an older counting instrument, such as an abacus.
The first mainframe computers were developed in the 1940s and 1950s. These room-sized computers relied upon technology such as vacuum tubes and transistors. They represented some of the first machines with robust calculating powers and paved the way for the further development of electronic calculators a few decades later.
In 1957, the Casio Computer Company released the Model 14-A calculator in Japan. It was the world’s first all-electric compact calculator. How compact was it? The relay technology it used was large enough that the calculator had to be built into a desk!
It would be four more years before the British Bell Punch/Sumlock Comptometer ANITA was announced as the world’s first all-electronic desktop calculator. ANITA used smaller vacuum tube technology, but it still weighed in at a hefty 33 pounds.
As computer technology improved and microprocessors were developed, calculators became smaller and cheaper. Calculators that would fit in your pocket eventually became available in the mid-1970s. By the 1980s, calculators had become affordable enough to become commonplace in many schools.
So how do these devices work? Most calculators rely on integrated circuits more commonly known as chips. Integrated circuits contain transistors that can be turned on and off with electricity to perform mathematical calculations.
The most basic calculations are addition, subtraction, multiplication, and division. The more transistors an integrated circuit has, the more advanced mathematical functions it can perform. Today’s scientific calculators, for example, can perform incredibly advanced mathematical calculations.
Like all other electronic devices, calculators work by processing information in binary form. We’re used to thinking of numbers in our normal base-ten system, in which there are ten digits to work with: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. The binary number system is a base-two system, which means there are only two digits to work with: 0 and 1. Thus, when you input numbers into a calculator, the integrated circuit converts those numbers to binary strings of 0s and 1s.
The integrated circuits then use those strings of 0s and 1s to turn transistors on and off with electricity to perform the desired calculations. Since there are only two options in a binary system (0 or 1), these can easily be represented by turning transistors on and off, since on and off easily represent the binary options (on = 0 and off = 1 or vice versa).
Once a calculation has been completed, the answer in binary form is then converted back to our normal base-ten system and displayed on the calculator’s display screen. Most calculator displays use inexpensive technologies common today, such as liquid crystal displays (LCD) or light-emitting diodes (LED).