A calculator is a device for performing numerical calculations. The type is considered distinct from both a calculating machine and a computer in that the calculator is a special-purpose device that may not qualify as a Turing machine. Although modern calculators often incorporate a general purpose computer, the device as a whole is designed for ease of use to perform specific operations, rather than for flexibility. A calculation is a deliberate process for transforming one or more inputs into one or more results. ... A calculating machine is a machine designed to come up with calculations (i. ... A computer is device or machine for processing information according to a program - a list of instructions. ... Artists conception of a universal Turing machine. ...

A basic arithmetic calculator.

The complexity of calculators varies with the intended purpose. A simple one with only four functions (addition, subtraction, multiplication and division and perhaps a single-number memory) may be useful for everyday activities such as shopping or checking a bill. More complex ones may include complex mathematical functions suitable to engineering or accounting as well as a substantial memory and the ability to execute moderately complex programs. Image File history File links Calculator. ... Image File history File links Calculator. ... Addition (or summation) is one of the basic operations of arithmetic. ... In mathematics, subtraction is one of the four basic arithmetic operations. ... In its simplest form, multiplication is a quick way of adding identical numbers. ... In mathematics, especially in elementary arithmetic, division is an arithmetic operation which is the reverse operation of multiplication, and sometimes it can be interpreted as repeated subtraction. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Licensure and Qualifications for the Practice of Engineering The Engineers Ring The Ritual of the Calling of an Engineer Engineering Disasters and Learning from Failure American Society of Engineering Education (ASEE) ASEE engineering profile (2003) PDF The Instititute of Electrical and Electronics Engineers, Inc. ... Accountancy (British English) or accounting (American English) is the process of maintaining, auditing, and processing financial information for business purposes. ... This article needs to be cleaned up to conform to a higher standard of quality. ...

Since the late 1980's, it has become common to incorporate simple calculators in other small devices, such as mobile phones, pagers or wrist watches! Events and trends The 1980s marked an abrupt shift towards more conservative lifestyles after the momentous cultural revolutions which took place in the 1960s and 1970s and the definition of the AIDS virus in 1981. ... A pager is an electronic device used to contact people via a Paging (telecommunications) network. ... Pocket watch A watch is a small portable clock that displays the current time and sometimes the current day, date, month and year. ...

Personal computers and personal digital assistants can perform general calculations in a variety of ways: Palm IIIxe PDA Personal digital assistants (PDAs or palmtops) are handheld devices that were originally designed as personal organizers, but became much more versatile over the years. ...

• computers often have a separate calculator program, varying from one that just emulates a simple calculator, such as Microsoft Calculator, to advanced spreadsheet programs such as Excel or OpenOffice.org Calc
• for more advanced calculations one can use a computer algebra program, such as Mathematica, Maple or Matlab.
• browsers can perform calculations using client-side scripting, e.g. using Client-side JavaScript by entering "javascript:alert(12*13)" in the address bar (the answer 156 appears in a separate alert window) or "document.write (12*13)" in a HTML file, preceded with "<script type="text/javascript">" and followed by "</script>".
• an interpreter or compiler for a general programming language can be used
• calculations can also be performed server-side, e.g. with the calculator feature of the Google search engine

In most developed countries, students use calculators for schoolwork. There was some initial resistance to the idea out of fear that basic arithmetic skills would suffer. There remains disagreement about the importance of the ability to perform calculations by hand or "in the head", with some curricula restricting calculator use until a certain level of proficiency has been obtained, while others concentrate more on teaching estimation techniques and problem-solving. A screenshot of Microsft Calculator running in Windows XP Microsoft Calculator is a calculation application for Microsoft Windows. ... A spreadsheet is a rectangular table (or grid) of information, often financial information. ... Microsoft Excel is a spreadsheet program written and distributed by Microsoft for computers using the Microsoft Windows operating system and for Apple Macintosh computers. ... OpenOffice. ... A computer algebra system (CAS) is a software program that facilitates symbolic mathematics. ... Mathematica is a widely-used computer algebra system originally developed by Stephen Wolfram and sold by his company Wolfram Research. ... Maple is a general purpose commercial computer algebra system. ... MATLAB refers to both the numerical computing environment and to its core programming language. ... Client-side scripting generally refers to the class of computer programs on the web that are executed client-side, by the users web browser, instead of server-side (on the web server). ... Client-side JavaScript (CSJS) is JavaScript that runs on client-side, hence is for client-side scripting. ... In computing, HyperText Markup Language (HTML) is a markup language designed for the creation of web pages and other information viewable in a browser. ... Software programs or applications that are on a local or remote server are called Server-Side programs Categories: Computer stubs ... Google offers a variety of services and tools besides its basic web search. ... Students attending a lecture at the Helsinki University of Technology Etymologically derived through Middle English from the Latin second-type conjugation verb stŭdērĕ, which means to direct ones zeal at; hence a student is one who directs zeal at a subject. ... Elementary arithmetic is the most basic kind of mathematics: it concerns the operations of addition, subtraction, multiplication, and division. ... Estimation is generally the calculation of an approximate or uncertain result, often based on approximate, uncertain, incomplete, or noisy data. ...

Overview

Modern calculators are electrically powered, most often by battery, and are made by numerous manufacturers, in countless shapes and sizes varying from cheap, give-away, credit-card sized models to more sturdy adding machine-like models with built-in printers. Only a very few companies develop and make modern professional engineering and finance calculators: The most well-known are Casio, Sharp, Hewlett-Packard (HP) and Texas Instruments (TI). Such calculators are good examples of embedded systems. They are also often complex enough to be programmed; calculator applications include algebraic equation solvers, financial models and even games. CASIO Calculator Casio, Inc. ... Sharp Corporation (シャープ株式会社 Shāpu Kabushiki Gaisha) is a Japan-based electronics manufacturer, founded in 1912. ... The Hewlett-Packard Company (NYSE: HPQ), commonly known as HP, is a very large, global company headquartered in Palo Alto, California, United States. ... Texas Instruments (NYSE: TXN), better known in the electronics industry as TI, is a company based in Dallas, Texas, renowned for developing and commercializing semiconductor and computer technology. ... An embedded system is a special-purpose computer system, which is completely encapsulated by the device it controls. ...

In the near past, mechanical and clerical aids such as abacuses, comptometers, Napier's bones, books of mathematical tables, slide rules, adding machines, were used for serious numeric work, and the word "calculator" denoted a person (most often male) who did such work for a living using such aids as well as pen and paper. This semi-manual process of calculation was tedious and error-prone. An abacus is a calculation tool, often constructed as a wooden frame with beads sliding on wires. ... A Comptometer is a type of mechanical (or electro-mechanical) adding machine. ... Napiers bones are an abacus invented by John Napier for calculation of products and quotients of numbers. ... Before calculators were cheap and plentiful, people would use mathematical tables —lists of numbers showing the results of calculation with varying variables— to simplify and drastically speed up computation. ... The slide rule is an analog computer, usually consisting of three interlocking calibrated strips and a sliding window, called the cursor. ... An adding machine is a type of calculator. ... Piece of paper Paper is a thin, flat material produced by the compression of fibres. ...

Electronic calculators

Today most calculators are handheld microelectronic devices, but in the past some calculators were as large as today's computers. The first mechanical calculators were mechanical desktop devices, which were soon replaced by electromechanical desktop calculators, and then by electronic devices using first thermionic valves, then transistors, then hard-wired integrated circuit logic. The tower of a personal computer. ... A mechanical calculator is a device that does computations without the aid of electricity. ... In electronics, a vacuum tube (American English) or (thermionic) valve (British English) is a device generally used to amplify a signal. ... Through hole transistors (tape measure marked in centimeters) The transistor is a solid state semiconductor device which can be used for amplification, switching, voltage stabilization, signal modulation and many other functions. ... An integrated circuit (IC) is a thin chip consisting of at least two interconnected semiconductor devices, mainly transistors, as well as passive components like resistors. ...

A pocket calculator is a small battery-powered or solar powered electronic digital computer made possible by integrated circuit and semiconductor technology. Typically they are limited to an 8–10 digit single-number display and a few basic functions of arithmetic, but some modern calculators have more of the features of a general-purpose computer. Pocket calculators rendered the slide rule obsolete. An integrated circuit (IC) is a thin chip consisting of at least two interconnected semiconductor devices, mainly transistors, as well as passive components like resistors. ... A semiconductor is a material with an electrical conductance that is intermediate to those of an insulator and a conductor. ... The slide rule is an analog computer, usually consisting of three interlocking calibrated strips and a sliding window, called the cursor. ...

Calculators vary in their capabilities. Some are limited to only basic arithmetic; others support trigonometric, statistical and other mathematical functions. The most advanced modern calculators are programmable, can display graphics, and include features of computer algebra systems. In mathematics, the trigonometric functions are functions of an angle, important when studying triangles and modeling periodic phenomena. ... Statistics is a type of data analysis which practice includes the planning, summarizing, and interpreting of observations of a system possibly followed by predicting or forecasting of future events based on a mathematical model of the system being observed. ... In mathematics, several functions are important enough to deserve their own name. ... A computer algebra system (CAS) is a software program that facilitates symbolic mathematics. ...

History

Origin: The Abacus

Chinese abacus.

Main article: Abacus

The first calculators were abacuses, and were often constructed as a wooden frame with beads sliding on wires. Abacuses were in use centuries before the adoption of the written Arabic numerals system and are still widely used by merchants and clerks in China and elsewhere. Scanned and uploaded by Malcolm Farmer Source: Article for abacus, 9th edition Encyclopedia Britannica, volume 1 (1875) This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... Scanned and uploaded by Malcolm Farmer Source: Article for abacus, 9th edition Encyclopedia Britannica, volume 1 (1875) This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... An abacus is a calculation tool, often constructed as a wooden frame with beads sliding on wires. ...

The 17th century

Wilhelm Schickard built the first automatic calculator called the "Calculating Clock" in 1623. Some 20 years later, in 1645, French philosopher Blaise Pascal invented the calculation device later known as Pascal's calculator, which was used for taxes in France until 1799. Wilhelm Schickard (born 1592 in Herrenberg - died 1635 in Tübingen) built the first automatic calculator in 1623. ... Blaise Pascal (June 19, 1623–August 19, 1662) was a French mathematician, physicist, and religious philosopher. ... A Pascaline, signed by Pascal in 1652 Blaise Pascal invented the second mechanical calculator, called alternatively the Pascaline or the Arithmetique, in 1645, the first being that of Wilhelm Schickard in 1623. ...

1930s to 1960s

Monroe mechanical digital calculator.

From approximately the 1930s through the 1960s, mechanical calculators were often used (see Mechanical Calculator under History of computing hardware). These desktop devices were motor-driven and had multiple columns of keys for each digit. Addition and subtraction were performed in a single operation, as on a conventional adding machine, but multiplication and division were accomplished by repeated mechanical additions and subtractions. Handheld mechanical calculators such as the Curta continued to be used until they were displaced by electronic calculators in the 1970s. Manual digital calculator by Monroe File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Manual digital calculator by Monroe File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... // Events and trends The 1930s were spent struggling for a solution to the global depression. ... The 1960s, or The Sixties, in its most obvious sense refers to the decade between 1960 and 1969, but the expression has taken on a wider meaning over the past twenty years. ... Computing hardware has been an essential component of the process of calculation and data storage since it became useful for numerical values to be processed and shared. ... Addition (or summation) is one of the basic operations of arithmetic. ... In mathematics, subtraction is one of the four basic arithmetic operations. ... In its simplest form, multiplication is a quick way of adding identical numbers. ... In mathematics, especially in elementary arithmetic, division is an arithmetic operation which is the reverse operation of multiplication, and sometimes it can be interpreted as repeated subtraction. ... The Curta was a small, hand-cranked mechanical calculator introduced in 1948. ...

In 1954, IBM demonstrated a large all-transistor calculator. In 1957, IBM released the first commercial all-transistor calculator (the IBM 608). The first handheld electronic calculators, as opposed to desktop ones, went on sale in 1970 with models from Japanese manufacturers Sharp and Canon weighing around 1.7 lb (770 g). 1954 was a common year starting on Friday of the Gregorian calendar. ... International Business Machines Corporation (IBM, or colloquially, Big Blue) (NYSE: IBM) (incorporated June 15, 1911, in operation since 1888) is headquartered in Armonk, NY, USA. The company manufactures and sells computer hardware, software, and services. ... Through hole transistors (tape measure marked in centimeters) The transistor is a solid state semiconductor device which can be used for amplification, switching, voltage stabilization, signal modulation and many other functions. ... 1957 was a common year starting on Tuesday of the Gregorian calendar. ... 1970 was a common year starting on Thursday. ... Sharp Corporation (シャープ株式会社 Shāpu Kabushiki Gaisha) is a Japan-based electronics manufacturer, founded in 1912. ... Canon logo Canon Inc. ...

1970s to mid-1980s

In the early 1970s, the Monroe EPIC programmable calculator came on the market. A large desk-top unit, with an attached floor-standing logic tower, it was capable of being programmed to perform many computer-like functions. However, the only branch instruction was an implied unconditional branch (GOTO) at the end of the operation stack, returning the program to its starting instruction. Thus, it was not possible to include any conditional branch (IF-THEN-ELSE) logic. During this era, the absence of the conditional branch was sometimes used to distinguish a programmable calculator from a computer. This article provides extensive lists of events and significant personalities of the 1970s. ... A conditional branch is a basic logical structure. ...

The first pocket-sized calculator, the Bowmar 901B (popularly referred to as The Bowmar Brain), measuring 5.2×3.0×1.5 in (131×77×37 mm), came out in the fall of 1971, with four functions and an eight-digit red LED display, for $240, while in August 1972 the four-function Sinclair Executive became the first slimline pocket calculator measuring 5.4×2.2×0.35 in (138×56×9 mm) and weighing 2.5 oz (70g). It retailed for around $150 (GB£79). By the end of the decade, similar calculators were priced less than $10 (GB£5). 1971 is a common year starting on Friday (click for link to calendar). ... Various light-emitting diodes (5 mm reds, 3 mm greens and yellows) A light-emitting diode (LED) is a semiconductor device that emits incoherent narrow-spectrum light when electrically biased in the forward direction. ... 1972 was a leap year that started on a Saturday. ... The Sinclair Executive was Clive Sinclairs first venture into the pocket calculator market. ... The pound sterling, which strictly speaking refers to basic currency unit of sterling, now the pound, is the currency of the United Kingdom (UK). ...

The first pocket calculator with scientific functions, i.e. the first slide rule-replacing model, was the 1972 HP-35 from Hewlett Packard (HP); it, along with all later HP engineering calculators, used reverse Polish notation (RPN) (where a calculation like "6 – 2" is performed by pressing "6", "Enter↑", "2", and "–"; instead of algebraically: "6", "–", "2", "="). The HP-35 was Hewlett-Packards first pocket calculator and the worlds first scientific pocket calculator (a calculator with trigonometric and exponential functions). ... The Hewlett-Packard Company (NYSE: HPQ), commonly known as HP, is a very large global company headquartered in Palo Alto, California, United States. ... Reverse Polish notation (RPN) , also known as postfix notation, is an arithmetic formula notation, derived from the Polish notation introduced in 1920 by the Polish mathematician Jan Łukasiewicz. ...

Most common among early scientific calculators was the TI-30 from Texas Instruments (TI). The first programmable hand-held calculator was the HP-65, in 1974; it had a capacity of 100 instructions, and could store and retrieve programs with a built-in magnetic card reader. A year later the HP-25C introduced continuous memory, i.e. programs and data were retained in memory during power-off. In 1979, HP released the first alphanumeric, programmable, expandable calculator, the HP-41C. It could be expanded with RAM (memory) and ROM (software) modules, as well as peripherals like bar code readers, microcassette and floppy disk drives, paper-roll thermal printers, and miscellaneous communication interfaces (RS-232, HP-IL, HP-IB). TI-30X IIS The TI-30 is a scientific calculator manufactured by Texas Instruments. ... Texas Instruments (NYSE: TXN), better known in the electronics industry as TI, is a company based in Dallas, Texas, renowned for developing and commercializing semiconductor and computer technology. ... The HP-65 was the first programmable handheld calculator in the world. ... 1974 is a common year starting on Tuesday (click on link for calendar). ... This page refers to the year 1979. ... Generally speaking, the term alphanumeric refers to anything that consists of only letters and numbers. ... The HP-41 series are programmable, expandable, handheld RPN calculators made by Hewlett-Packard from 1979 to 1990. ... Look up RAM and random access memory in Wiktionary, the free dictionary Different types of RAM. From top to bottom: DIP, SIPP, SIMM 30 pin, SIMM 72 pin, DIMM, DDR DIMM Random access memory (sometimes random-access memory), commonly known by its acronym RAM, is a type of computer storage... Rom is also the name of a toy and comic book character Rom (Spaceknight). ... Wikipedia encoded in Code 128_B A barcode (also bar code) is a machine-readable representation of information in a visual format on a surface. ... Categories: Stub | Audio storage ... A floppy disk is a data storage device that is composed of a circular piece of thin, flexible (i. ... Direct thermal printers create an image by selectively heating coated paper when the paper passes over the thermal print head. ... RS-232 (also referred to as EIA RS-232C or V.24) is a standard for serial binary data interchange between a DTE (Data terminal equipment) and a DCE (Data communication equipment). ... The HP-IL (Hewlett-Packard Interface Loop) is a short range network cable enabling several devices such as printers, floppy disk drives, tape readers, etc. ... The Hewlett-Packard Instrument Bus (HP-IB), is a short-range digital communications cable standard developed by Hewlett-Packard (HP) in the 1970s for connecting electronic test and measurement devices (e. ...

Mid-1980s to present

A TI-84 Plus graphing calculator from Texas Instruments.

A screenshot of a 3D wire frame graph on a TI-89 calculator.

The two leading manufacturers, HP and TI, released steadily more feature-laden calculators during the 1980s and 90s. At the turn of the millennium, the line between a graphing calculator and a PDA/ handheld computer was not always clear (forgetting the keyboard for the sake of the argument), as some very advanced calculators such as the TI-89 and HP-49G could differentiate and integrate functions, run word processing and PIM software, and connect by wire or IR to other calculators/computers. Download high resolution version (335x660, 74 KB)TI-84 Plus greeting Wikipedia. ... Download high resolution version (335x660, 74 KB)TI-84 Plus greeting Wikipedia. ... TI-84 Plus The TI-84 Plus (there is no plain TI-84) is a graphing calculator made by Texas Instruments that came out spring 2004. ... A TI-89 Titanium Screen Capture - By User:Nrbelex This is a screenshot of copyrighted computer software. ... A TI-89 Titanium Screen Capture - By User:Nrbelex This is a screenshot of copyrighted computer software. ... A wire frame model is a visual presentation of an electronic representation of a three dimensional or physical object used in 3D computer graphics. ... A TI-89 The TI-89 and the TI-89 Titanium are graphing calculators developed by Texas Instruments. ... A graphing calculator is a special kind of scientific/engineering calculator that is able to display and/or analyze mathematical function graphs. ... Handheld devices (also known as handhelds) are pocket-sized computing devices that are rapidly gaining popularity as the access to information in every walk of life becomes more and more mission critical. ... The TI-89 and the TI-89 Titanium are graphing calculators developed by Texas Instruments. ... The HP-49G series are Hewlett-Packard (HP)-manufactured graphing calculators. ... The derivative in mathematics (specifically, differential calculus) is a quantity that measures, on continuous functions, the limit of a rate of change, , as approaches 0. ... Integration may be any of the following: In the most general sense, integration may be any bringing together of things: the integration of two or more economies, cultures, religions (usually called syncretism), etc. ... In mathematics, a function is a relation, such that each element of a set (the domain) is associated with a unique element of another (possibly the same) set (the codomain, not to be confused with the range). ... Word processing, in its now-usual meaning, is the use of a word processor to create documents using computers. ... A Personal Information Manager is a software application that keeps track of personal information such as: E-mails Address books Calendars Task lists Task scheduling (invitations etc) Notices There are several software packages that do this. ... Image of a small dog taken in mid-infrared (thermal) light (false color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than visible light, but shorter than microwave radiation. ...

In March 2002, HP announced that the company would no longer produce calculators, which was hard to fathom for some fans of the company's products; the HP-48 range in particular had an extremely loyal customer base. Nevertheless, HP restarted their production of calculators in late 2003. The new models, however, reportedly didn't have the mechanical quality and sober design HP's earlier calculators were famous for (instead featuring the more "youthful" look and feel of contemporary competing designs from TI). 2002 is a common year starting on Tuesday of the Gregorian calendar. ... The HP-48 is a series of graphing calculators produced by Hewlett-Packard (HP) from 1990 until 2003, using Reverse Polish notation (RPN). ...

The business calculator HP-12C is still produced. It was introduced in 1981 and is still being made with nearly no changes. In 2003 several new models were released, including an improved version of the HP-12C, the "HP-12C platinum edition". The HP-12C is a financial calculator made by Hewlett-Packard. ...

Trivia

• The word "calculator" is occasionally used as a pejorative term to describe an inadequately capable general-purpose microcomputer. The synonym of this meaning is "bitty box", as discussed in the Jargon file.

• A curious episode of the mid 1970s involved the Melcor 635, a scientific calculator with a bug in its trigonometric functions. Because the CORDIC algorithms used in most calculators cannot compute the inverse trigonometric functions of zero, these need to be hardcoded — and some engineer at Melcor got it wrong. For any input other than exactly zero, even for instance 1.0E-99, the calculator worked correctly; the user simply had to remember not to compute the arc-cosine of zero. The company discovered this after making 50,000 calculators. The upshot was an advertisement in Scientific American headlined 'Somebody Goofed', offering these calculators for sale at half-price.

• As many schoolchildren and students know, some words and simple phrases can be written using an ordinary seven-segment display calculator; this involves entering certain numbers and then viewing the resulting words by turning the calculator display upside-down. Some of the larger words/phrases obtainable in this fashion are:
  • BOOB = 8008, BOOBIES = 5318008, BOOBLESS = 55378008
  • LEgS = 5637
  • hELL = 7734, hELLO = 0.7734
  • gO2hELL = 7734206
  • DEBIL = 71830 ("moron" or "imbecil" in Polish and Czech, also "retarded" in German and "weak" in Spanish)
  • hEI = 134 ("hi" in Norwegian and in Finnish)
  • BEBE = 3838 ("baby" in Spanish and French)
  • BOLILLO = 0.771708 ("Piece of bread" in Spanish)
  • OhIO = 0.140
  • ShELLOIL = 710.77345 (following a series of hypothetical computations on monopoly theory)
  • ESEL = 7353 ("donkey" or "moron" in German)
  • OSEL = 7350, OSLE = 3750 ("donkey" or "moron" in Czech, the second one is the vocative case "you, donkey!")
  • OhOLSIhO = 0.4157040 ("shaveyourdick" in Czech)

Apple IIc Generally, a microcomputer is a computer with a microprocessor (µP) as its CPU. Another general characteristic of these computers is that they occupy physically small amounts of space. ... The Jargon File is a glossary of hacker slang. ... A computer bug is an error, flaw, mistake, failure, or fault in a computer program that prevents it from working correctly or produces an incorrect result. ... Trigonometry (from the Greek trigonon = three angles and metro = measure) is a branch of mathematics dealing with angles, triangles and trigonometric functions such as sine, cosine and tangent. ... CORDIC (for COordinate Rotation DIgital Computer) is a simple and efficient algorithm to calculate hyperbolic and trigonometric functions. ... 0 (zero) or nought is both a number and a numeral. ... ... In mathematics, the trigonometric functions are functions of an angle, important when studying triangles and modeling periodic phenomena. ... Scientific American is one of the oldest and most serious popular-science magazines. ... A seven segment display (sometimes written as 7-segment display) is a form of display that predates the now ubiquitous dot-matrix displays. ... The vocative case is the case used for a noun identifying the person being addressed, found in Latin among other languages. ...

See also

General interest:

• Category:Calculators
• History of computing hardware

Mechanical calculators: Computing hardware has been an essential component of the process of calculation and data storage since it became useful for numerical values to be processed and shared. ...

• Abacus
• Napier's bones
• Comptometer
• Mercedes (calculator)
• Adding machine
• Addiator
• Curta

Electronic calculators: An abacus is a calculation tool, often constructed as a wooden frame with beads sliding on wires. ... Napiers bones are an abacus invented by John Napier for calculation of products and quotients of numbers. ... A Comptometer is a type of mechanical (or electro-mechanical) adding machine. ... The Mercedes-Euklid is a German-invented calculator from the early twentieth century. ... An adding machine is a type of calculator. ... The Addiator was a mechanical add/subtract calculator, made by Addiator Gesellschaft, Berlin. ... The Curta was a small, hand-cranked mechanical calculator introduced in 1948. ...

• List of calculators

This is a list of types of calculators, many of which are obsolete but hoarded by legions of admiring collectors. ...

Patents

• U.S. Patent 2668661 – Complex computer – G. R. Stibitz (electromechanic device that would calculate, record, and print results)
• U.S. Patent 3819921 – Miniature electronic calculator – J. S. Kilby (TI electromechanic device)

George Stibitz (April 20, 1904 – January 31, 1995) was a Bell Labs researcher mostly known for his 1930s and 1940s work on the realization of Boolean logic digital circuits using electromechanical relays as the switching element. ... Jack Kilby holding an old calculator and one of the newest. ...

External links

• Online Calculators and Converters
• Online Calculator Software
• Online deep space SETI range calculator
• Scientific Calculator - Scientific notation, hex, octal, decimal, binary, and math functions. Requires JavaScript. (from ostermiller.org)
• The Old Calculator Web Museum
• Calculator Museum
• Museum of Soviet Calculators
• Soviet Calculators Collection
• Vintage Calculators
• various calculators
• Broken Calculator
• GraphCalc – an Open Source graphing calculator program
• HiDigit scientific calculator
• The Museum of HP Calculators (slide rules/mech. section)
• HP Calculator Wiki
• On TI's US Patent No. 3,819,921