The earliest abacus dates back to Sumeria in 2500 B.C. Unfortunately, while the abacus could be used efficiently and quickly for addition and subtraction, it’s a limited device and doesn’t lend itself well to division and multiplication. In 1617, the Scottish mathematician John Napier came up with the idea of a multiplying table that would assist in performing calculations by representing multiplication operations in multiplication tables inscribed on thin rods. In 1623, Wilhelm Schickard first conceived of a calculating clock, which consisted of a multiplying device and a mechanism for recording the results of operations. Unlike modern calculators, which can perform an array of complex computations, the first calculators were adding machines that could perform basic arithmetic operations on whole numbers and fractions. However, they were limited to addition, subtraction, multiplication and division. Operations were entered into the machine using the machine’s bulky keyboard. The first true calculating tool was the Pascal calculator, invented by the French mathematician Blaise Pascal in 1642. Pascal calculators were revolutionary for their innovative calculating ability, but they were never widely produced. Similar mechanical calculating machines were designed and produced in limited production runs throughout the 18th and 19th centuries.

In 1851, Thomas de Colmar released a calculating machine that was easier to produce than all previous machines and could be used in office settings. However, though it was an improvement, it was far less compact than today’s calculators. The first widely produced and sold calculators arrived in the 20th century. The hand-held calculator, called the Curta, was invented by Curt Herzstark in 1945 and looked like a pepper grinder.

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