# Adding machine

An **adding machine** or a **calculator** is a device that realizes mathematical calculations. The first calculators were the mechanical ones made from gears, draw bars and cranks.

First electric calculators were developed between 1940-1945. They were used as tools for arithmetic operations and were very used between the XIX and XX centuries in domains like engineering, research, financial calculations and banking, cashiers and others.

Besides general use calculators there are those projected for specific markets for example scientific computers that realize more complex operations than arithmetic like trigonometry and statistics. Graphing calculators can be used for graphic functions defined by real lines.

The electronic calculators based on integrated circuits have small dimensions, nowadays being very small - the size of a watch.

Most computers include the following buttons: 1,2,3,4,5,6,7,8,9,0 ,+,-,×,÷,.,=,%. Some include the buttons 00 and 000 for large calculations.

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## History

In the past mechanic materials like abacus, mechanic abacus, books with mathematical tables, rulers or mechanic machines were used for the work with numbers. This semi - manual process was very tiring and error prone.

Modern calculators are electric and have variable sizes. They became popular in late 60s, when their cost became very low. In the 80s almost anyone could afford a calculator and in the 90s they became very common in schools in the idea that students should be released by the base calculations so they focus on concepts.

## Origins - Abacus

The first calculators were abathia, mostly built on a wood frame with beads. Abathias were used centuries before the Arabic system was implemented and are still used today by some merchants, fishermen and recorders in Africa and Asia. For centuries, there have been used devices to ease the calculations. The oldest were probably sticks. Later were clay forms, representing elements like grain and animal reserves.

The Abacus was designed by Egyptian mathematicians in 2000 B.C. and were used for arithmetic operations. The Roman Abacus was used in Babylonia from 2400 B.C.

In ancient and medieval times there have been built various analogical calculators to realize astronomical calculations. These include the Antikythera and Astrolabe mechanism from ancient Greece (about 150 - 100 B.C) which are considered to be the first analogical calculators.

## The XVII century

The Scottish mathematician and physicist John Napier realized that operations of multiplication and division can be done with the help of addition and subtraction operations and he produced the first logarithmic tables.

In 1622 William Oughtred invented the calculation ruler. That is not a time to waste it! Detect trustworthy service and pay for essays from them. Because real numbers can be represented as distances or time intervals on a line, the calculation ruler allowed the realization of multiplication and division operations faster than before. These devices were used by generations of engineers and other professionals using math up to the time the pocket calculator was invented.

The German mathematician Wilhelm Schickard built the first mechanical calculator in 1623 becoming the "father of the calculation era". Because his calculator used gears and tools initially developed for clocks it was called the calculating clock. This calculator was used by his friend Johannes Kepler.

About 20 years later in 1642 the French philosopher Blaise Pascal invented the calculating device known as "Pascaline" used to calculate France's taxes until 1799. One original Pascaline is kept at the Zwinger Museum. Next it was a machine invented by Gottfried Wilhelm von Leibniz in 1671.

## The XIX century

In 1820 Thomas de Colmar patented Artihmometer the first successful computer that could add, subtract and multiply. Also it could do division operations but with some help from the user.

In 1822 Charles Babbage projected a mechanic calculator called "differential engine" capable to memorize and manipulate seven numbers of 31 decimals.

In 1872 Frank Baldwin invented the Messier calculator.

In 1891 William S. Burroughs started the producing of calculators with printing (paper role). Burroughs Corporation became one of the most important companies in accounting machines production and calculators business in general. In 1893 was produced the calculator that allowed direct multiplication with any digit - one crank turn for any digit of the multiplicator.

## 1900 - 1960

The Dalton machine was the first calculator that was using only ten keys. In 1948 Curt Herzstark introduced on the market the mini-calculator Curta which could be held in one hand.

From the early 1990s until the 60s mechanic calculators dominated the office calculators market. Among the great suppliers from USA were Friden, Monroe and CSM / Merchant. These kinds of calculators had an engine and the results were displayed on dials.

## Concerns regarding use

In most countries students use calculators to solve problems and to do school homework. There has been a hostility against the idea of calculator use in school based on the reason that students would lose their abilities to solve operations mentally. So the focus was on the capacity of doing mental calculations being forbidden the calculator use.

Researches show that inappropriate orientation in using calculation tools can restrict the way a student thinks.

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