Calculator

Calculator, handheld device that performs mathematical calculations. A calculator can also be a program on a computer that simulates a handheld calculator or offers more sophisticated calculation features.

A standard calculator is rectangular in shape and has a keypad through which numbers and operations are entered, as well as a display on which the entered numbers and the results of calculations are shown. Modern calculators can perform many types of mathematical computations, as well as permit the user to store and access data from memory. Common handheld calculators have the ability to use complicated geometric, algebraic, trigonometric, statistical, and calculus functions. Many can also be programmed for specialized tasks. Calculators operate on electrical power supplied by either batteries, solar cells, or standard electrical current. Modern calculators have digital displays, usually using some form of LCD (liquid crystal display).

Calculator programs are common accessories included with most personal computer operating systems. For example, both the Macintosh and Windows operating systems have a simple desktop calculator program.

While the calculator is a very modern invention, machines able to perform addition and subtraction have existed for centuries. The abacus, a simple instrument for carrying out arithmetic operations, has been used by many cultures and dates back to ancient times. Another calculating instrument called the slide rule was invented in the early 1600s by the English mathematician William Oughtred. The slide rule was based on logarithms and made multiplication and division much easier. Engineers and scientists used slide rules until the introduction of calculators in the early 1970s.

The invention of the calculating machine is commonly credited to the French mathematician Blaise Pascal. In 1642 Pascal created a machine to free his father, who was a tax collector, from the tedious task of adding columns of numbers. Pascal’s machine used a complicated arrangement of numbered wheels connected by gears, which could add and subtract numbers up to nine digits long.

Until the late 1960s, hundreds of different types of calculating machines were invented that utilized many different technologies. Two of the most popular were the stepped-drum and pin-wheel mechanisms. These early calculators, even when refined for the desktop, were large, heavy, and expensive, compared to today’s calculators. Earlier models required the user to press a hand lever to turn the calculating mechanism. Later versions used electrical power to turn the mechanism. Most early calculators used paper tape to print typewritten numbers, operations, and results. For the most part, these mechanical devices could only perform four basic operations: addition, subtraction, multiplication, and division.

In 1967 a team of three engineers from Texas Instruments, Inc. invented the portable, electronic, handheld calculator. Jack Kilby, widely known as the inventor of the integrated circuit (IC), or computer chip, along with Jerry Merryman and James Van Tassel, built an IC-based, battery-powered miniature calculator that could add, subtract, multiply, and divide. This basic calculator could accept 6-digit numbers and display results as large as 12 digits. The prototype of this device is now displayed in the Smithsonian Institution, based in Washington, D.C.