It's easy to take the calculators that we own for granted. After all, they’re everywhere: in our phones, on the internet, in our school bags, and even in the school store. These devices, which are now widely used in many fields and institutions, come from a long line of machines and tools dating all the way back to ancient civilizations. Think ancient Greece, China, or Egypt, for example. The evolution of these rudimentary calculators into powerful pocket machines directly parallel the advancement of technologies and mathematics of their respective times. Let’s take a trip down memory lane and look at the history of calculators.
Almost 5000 years ago, basic arithmetic was done with fingers, sticks, or whatever you could find around yourself. Enter: the Abacus. Created c.~3000 BC, The abacus, also known as the “counting frame,” was used to add and subtract large numbers. This primitive tool used sexagesimal, or base 60, counting system. Now that may sound complicated at first but it’s fairly simple and easy to understand. Each column represents a tens place, and each “heavenly” bead above the “reckoning bar” is worth 5 units of its 10s place, while the 4 “earthly” beads below represents 1 unit in its 10s place. While not widely used anymore, the abacus is still used by merchants and teachers in certain countries.
Although it has has only existed for a fraction of the time of its predecessor, one can’t deny the slide rule’s persistency and importance in mathematics over the past 400 years. As its name implies, the slide rule is about 12 inches long, cut along its length into three pieces, with the middle one sliding back and forth. Not only was this ruler able to add and subtract, but also multiply, divide, calculate square roots, and calculate logarithms. Ever since the slide rule was invented by William Oughtred-who was inspired by John Napier’s discovery of the logarithm-in the mid-1600s, it hadn’t gone through many design changes during its lifetime because of its size and intuitiveness. It was used by NASA to engineer the rockets for Apollo 11 and MIT’s museum even had a three year long exhibit dedicated to the instrument.
There isn’t necessarily one version of a mechanical or electric calculator that has had as much impact as any of the aforementioned calculators. Unlike those instruments, these calculators have gone through many stages of development over hundreds of years and have become more sophisticated in that time. The first design for a mechanical calculator surprisingly came around the birth of the slide rule in the 1600s from William Schickard, called the Calculating Clock. The actual device itself wasn’t constructed until the mid 1900s, but the time in between was no dead period for the calculators. Following the work of famous mathematicians Pascal and Leibniz, Frank Baldwin created the first commercially spread mechanical calculator, the pinwheel calculator. It used gears, pins, and discs among other kinds of parts in its design and could perform the four basic arithmetic functions. The 20th century saw the introduction of electrical components into mechanical calculators and eventually, fully electrical calculators. The Madas 20AZS was a mechanical gear-based calculator that was electrically driven and developed in the 1950s. During the 1960s, electrical calculators were tabletop size and were priced around the range of a family car. These large devices, such as the Anita Mk VIII, used vacuum tubes which controlled electron flow in a fixed environment. Vacuum tubes were replaced by transistors, and electric calculators became battery powered and hand-held. The first of these, code named the “Cal-Tech,” began development by Texas Instruments in 1965. This is when hand held calculators were all the rage, and in 1972 came the first scientific calculator: the Hewlett Packard HP-35. Going beyond the four basic functions, the HP-35 dethroned the slide rule as the king of mathematics, computer science, and engineering. The HP-35 could perform logarithms, square roots, or trigonometric functions, you name it. It and its successor, the HP-65 (the first programmable scientific calculator) became the template for most modern calculators seen in offices, classrooms, etc.
Every “era” of the calculator represents a greater development in STEM. The abacus existed when early civilizations were adopting counting systems and the basic operations. Mathematical discoveries in the 17th century like logarithms along with more complex operations like exponents and roots called for the slide rule. Even in an age without complicated algorithms or programs, the slide rule managed to aid mathematicians and scientists all the way until the late 20th century. The invention of the first modern scientific calculators was built upon years and years of discoveries in mechanical and electrical engineering. With the growth of the internet and hand-held technology, many students and professionals today use graphing calculators, programs like Desmos and Mathematica, or simply the calculators on their phones.