A calculator is a small (often pocket-sized), usually inexpensive electronic device used to perform the basic operations of arithmetic Arithmetic or arithmetics is the oldest and most elementary branch of mathematics, used by almost everyone, for tasks ranging from simple day-to-day counting to advanced science and business calculations. It involves the study of quantity, especially as the result of combining numbers. In common usage, it refers to the simpler properties when. Modern calculators are more portable than most computers A computer is a programmable machine that receives input, stores and manipulates data//information, and provides output in a useful format, though most PDAs A personal digital assistant is a mobile device, also known as a palmtop computer. PDAs are used to organize a person's life by taking notes, holding contacts, and connecting to the Internet. Newer PDAs commonly have color screens and audio capabilities, enabling them to be used as mobile phones (smartphones), web browsers, or portable media are comparable in size to handheld calculators.
The calculator has its history in mechanical devices such as the abacus The abacus, also called a counting frame, is a calculating tool used primarily in parts of Asia for performing arithmetic processes. Today, abacuses are often constructed as a bamboo frame with beads sliding on wires, but originally they were beans or stones moved in grooves in sand or on tablets of wood, stone, or metal. The abacus was in use and slide rule The slide rule, also known colloquially as a slipstick, is a mechanical analog computer. The slide rule is used primarily for multiplication and division, and also for functions such as roots, logarithms and trigonometry, but is not normally used for addition or subtraction. In the past, mechanical clerical aids such as abaci The abacus, also called a counting frame, is a calculating tool used primarily in parts of Asia for performing arithmetic processes. Today, abacuses are often constructed as a bamboo frame with beads sliding on wires, but originally they were beans or stones moved in grooves in sand or on tablets of wood, stone, or metal. The abacus was in use, comptometers, Napier's bones, books of mathematical tables Before calculators were cheap and plentiful, people would use mathematical tables —lists of numbers showing the results of calculation with varying arguments— to simplify and drastically speed up computation. Tables of logarithms and trigonometric functions were common in math and science textbooks, slide rules The slide rule, also known colloquially as a slipstick, is a mechanical analog computer. The slide rule is used primarily for multiplication and division, and also for functions such as roots, logarithms and trigonometry, but is not normally used for addition or subtraction, or mechanical adding machines An adding machine is a type of calculator, usually specialized for bookkeeping calculations. In the United States, the earliest adding machines were usually built to read in dollars and cents. Adding machines were ubiquitous office equipment until they were phased out in favor of personal computers, beginning in about 1985. The machines were were used for numeric work. This semi-manual process of calculation was tedious and error-prone. The first digital mechanical calculator was invented in 1623 and the first commercially successful device was produced in 1820. The 19th and early 20th centuries saw improvements to the mechnical design, in parallel with analog computers An analog computer is a form of computer that uses the continuously-changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved. In contrast, digital computers represent varying quantities incrementally, as their numerical values change; the first digital electronic calculators were created in the 1960s, with pocket-sized devices becoming available in the 1970s.
Modern calculators are electrically powered (usually by battery and/or solar cell A solar cell is a device that converts the energy of sunlight directly into electricity by the photovoltaic effect. Sometimes the term solar cell is reserved for devices intended specifically to capture energy from sunlight such as solar panels and solar cells, while the term photovoltaic cell is used when the light source is unspecified) and vary from cheap, give-away, credit-card sized models to sturdy adding machine-like models with built-in printers. They first became popular in the late 1960s as decreasing size and cost of electronics made possible devices for calculations, avoiding the use of scarce and expensive computer resources. By the 1980s, calculator prices had reduced to a point where a basic calculator was affordable to most. By the 1990s they had become common in math classes in schools, with the idea that students could be freed from basic calculations and focus on the concepts.
Computer operating systems as far back as early Unix Ancient UNIX is a term coined by Santa Cruz Operation[citation needed] to describe early releases of the Unix code base released prior to Unix System III, particularly the Research Unix releases prior to and including Version 7 (the base for UNIX/32V as well as later developments of AT&T Unix) have included interactive calculator programs such as dc This translates into "push four and five onto the stack, then, with the multiplication operator, pop two elements from the stack, multiply them and push the result back on the stack." Then the 'p' command is used to examine the top element on the stack and hoc, and calculator functions are included in almost all PDA-type The term PDA was first used on January 7, 1992, by Apple Computer CEO John Sculley at the Consumer Electronics Show in Las Vegas, Nevada, referring to the Apple Newton. In 1996, Nokia introduced the first mobile phone with full PDA functionality, the 9000 Communicator, which has since grown to become the world's best-selling PDA and which spawned devices (save a few dedicated address book and dictionary devices).
In addition to general purpose calculators, there are those designed for specific markets; for example, there are scientific calculators A scientific calculator is a type of electronic calculator, usually but not always handheld, designed to calculate problems in science , engineering, and mathematics. They have almost completely replaced slide rules in almost all traditional applications, and are widely used in both education and professional settings which focus on operations slightly more complex than those specific to arithmetic - for instance, trigonometric Trigonometry is a branch of mathematics that studies triangles. Trigonometry deals with the relationships between the sides and angles of triangles and with trigonometric functions, which describe those relationships, angles in general, and the motion of waves and statistical Statistics is the formal science of making effective use of numerical data relating to groups of individuals or experiments. It deals with all aspects of this, including not only the collection, analysis and interpretation of such data, but also the planning of the collection of data, in terms of the design of surveys and experiments calculations. Some calculators even have the ability to do computer algebra A computer algebra system is a software program that facilitates symbolic mathematics. The core functionality of a CAS is manipulation of mathematical expressions in symbolic form. Graphing calculators A graphing calculator typically refers to a class of handheld calculators that are capable of plotting graphs, solving simultaneous equations, and performing numerous other tasks with variables. Most popular graphing calculators are also programmable, allowing the user to create customized programs, typically for scientific/engineering and can be used to graph functions defined on the real line, or higher dimensional Euclidean space In mathematics, Euclidean space is the Euclidean plane and three-dimensional space of Euclidean geometry, as well as the generalizations of these notions to higher dimensions. The term “Euclidean” is used to distinguish these spaces from the curved spaces of non-Euclidean geometry and Einstein's general theory of relativity. They often serve other purposes, however.
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Design
Scientific calculator displays of fractions and decimal equivalentsMost calculators contain the following buttons: 1,2,3,4,5,6,7,8,9,0,+,-,×,÷ (/),.,=,%, and ± (+/-). Some even contain 00 and 000 buttons to make larger calculations easier to compute.
Some fractions such as 2⁄3 are awkward to display on a calculator display as they are usually rounded to 0.66666667. Also, some fractions such as 1⁄7 which is 0.14285714285714 (to fourteen significant figures The significant figures of a number are those digits that carry meaning contributing to its precision (see entry for Accuracy and precision). This includes all digits except:) can be difficult to recognize in decimal form; as a result, many scientific calculators are able to work in vulgar fractions A fraction is a number that can represent part of a whole and/or mixed numbers.
In most countries, students The word student is etymologically derived through Middle English from the Latin second-type conjugation verb studēre, meaning "to direct one's zeal at"; hence a student could be described as "one who directs zeal at a subject". In its widest use, student is used for anyone who is learning use calculators for schoolwork. There was some initial resistance to the idea out of fear that basic arithmetic skills Elementary arithmetic is the simplified portion of arithmetic which is considered necessary and appropriate during primary education. It includes the operations of addition, subtraction, multiplication, and division. It is taught in elementary school would suffer. There remains disagreement about the importance of the ability to perform calculations "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 Estimation is the calculated approximation of a result which is usable even if input data may be incomplete or uncertain techniques and problem-solving. Research suggests that inadequate guidance in the use of calculating tools can restrict the kind of mathematical thinking that students engage in.[1] Others have argued that calculator use can even cause core mathematical skills to atrophy, or that such use can prevent understanding of advanced algebraic concepts.
Calculators versus computers
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The fundamental difference between a calculator and computer A computer is a programmable machine that receives input, stores and manipulates data//information, and provides output in a useful format is that a computer can be programmed A computer program is a sequence of instructions written to perform a specified task for a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute the instructions. The same program in its human- in a way that allows the program to take different branches according to intermediate results, while calculators are pre-designed with specific functions such as addition, multiplication, and logarithms built in. The distinction is not clear-cut: some devices classed as programmable calculators have programming functionality, sometimes with support for programming languages such as RPL or TI-BASIC.
The market for calculators is extremely price-sensitive, to an even greater extent than the personal computer market; typically the user buys the least expensive model having a specific feature set, but does not care much about speed (since speed is constrained by how fast the user can press the buttons). Thus designers of calculators strive to minimize the number of logic elements on the chip, not the number of clock cycles needed to do a computation.
For instance, instead of a hardware multiplier, a calculator might implement floating point In computing, floating point describes a system for representing numbers that would be too large or too small to be represented as integers. Numbers are in general represented approximately to a fixed number of significant digits and scaled using an exponent. The base for the scaling is normally 2, 10 or 16. The typical number that can be mathematics with code in ROM Read-only memory is a class of storage media used in computers and other electronic devices. Because data stored in ROM cannot be modified (at least not very quickly or easily), it is mainly used to distribute firmware (software that is very closely tied to specific hardware, and unlikely to require frequent updates), and compute trigonometric functions with the CORDIC CORDIC (for COordinate Rotation DIgital Computer) is a simple and efficient algorithm to calculate hyperbolic and trigonometric functions. It is commonly used when no hardware multiplier is available (e.g., simple microcontrollers and FPGAs) as the only operations it requires are addition, subtraction, bitshift and table lookup algorithm because CORDIC does not require hardware floating-point. Bit serial In telecommunication and computer science, serial communication is the process of sending data one bit at one time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent together, on a link with several parallel channels. Serial communication is used for all long-haul logic designs are more common in calculators whereas bit parallel In telecommunication and computer science, parallel communication is a method of sending several data signals simultaneously over several parallel channels. It contrasts with serial communication; this distinction is one way of characterizing a communications link designs dominate general-purpose computers, because a bit serial design minimizes chip complexity, but takes many more clock cycles. (Again, the line blurs with high-end calculators, which use processor chips associated with computer and embedded systems design, particularly the Z80 The Zilog Z80 is an 8-bit microprocessor designed and sold by Zilog from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes. The Z80 and its derivatives and clones make up one of the most commonly used CPU families of all time, and, along with the MOS Technology 6502 family,, MC68000, and ARM The ARM is a 32-bit reduced instruction set computer instruction set architecture (ISA) developed by ARM Holdings. It was known as the Advanced RISC Machine, and before that as the Acorn RISC Machine. The ARM architecture is the most widely used 32-bit ISA in terms of numbers produced. They were originally conceived as a processor for desktop architectures, as well as some custom designs specifically made for the calculator market.)
History
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Origin: the abacus
Suanpan (the number represented in the picture is 6,302,715,408) Main article: Abacus The abacus, also called a counting frame, is a calculating tool used primarily in parts of Asia for performing arithmetic processes. Today, abacuses are often constructed as a bamboo frame with beads sliding on wires, but originally they were beans or stones moved in grooves in sand or on tablets of wood, stone, or metal. The abacus was in useThe first calculators were abathia, and were often constructed as a wooden frame with beads sliding on wires. Abathias were in use centuries before the adoption of the written Arabic numerals The Arabic numerals or Hindu numerals or Hindu-Arabic numerals are the ten digits . They are descended from the Hindu-Arabic numeral system developed by Indian mathematicians, by which a sequence of numerals such as "975" is read as a whole number. The Indian numerals were adopted by the Persian mathematicians in India, and passed on to system and are still used by some merchants, fishermen and clerks in Africa, Asia, and elsewhere.
Other early calculators
Devices have been used to aid computation for thousands of years, using one-to-one correspondence In mathematics, a bijection, or a bijective function is a function f from a set X to a set Y with the property that, for every y in Y, there is exactly one x in X such that f = y and no unmapped element exists in either X or Y with our fingers.[2] The earliest counting device was probably a form of tally stick Tally sticks first appear as notches carved on animal bones, in the Upper Paleolithic. A notable example is the Ishango Bone. Later record keeping aids throughout the Fertile Crescent The Fertile Crescent is a region in Western Asia. It includes the comparatively fertile regions of Mesopotamia and the Levant, delimited by the dry climate of the Syrian Desert to the south and the Anatolian highlands to the north. The region is often considered the cradle of civilization, saw the development of many of the earliest human included clay shapes, which represented counts of items, probably livestock or grains, sealed in containers.[3]
The counter abacus was devised by Egyptian mathematicians in Egypt in 2000 BC. It was used for arithmetic tasks. The Roman abacus The Romans developed the Roman hand abacus, a portable, but less capable, base-10 version of the previous Babylonian abacus. It was the first portable calculating device for engineers, merchants and presumably tax collectors. It greatly reduced the time needed to perform the basic operations of Roman arithmetic using Roman numerals was used in Babylonia Babylonia was an ancient cultural region in central-southern Mesopotamia , with Babylon as its capital. Babylonia emerged when Hammurabi (fl. ca. 1696 – 1654 BC, short chronology) created an empire out of the territories of the former Akkadian Empire. Babylonia adopted the written Semitic Akkadian language for official use, and retained the as early as 2400 BC. Since then, many other forms of reckoning boards or tables have been invented. In a medieval counting house A counting house, or compting house, literally is the building, room, office or suite in which a business firm carries on operations, particularly accounting. By an obvious synecdoche, it has come to mean the accounting operations of a firm, however housed. The term is British in origin and is primarily used in the context of the 19th century or, a checkered cloth would be placed on a table, and markers moved around on it according to certain rules, as an aid to calculating sums of money (this is the origin of "Exchequer" as a term for a nation's treasury).
A number of analog computers An analog computer is a form of computer that uses the continuously-changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved. In contrast, digital computers represent varying quantities incrementally, as their numerical values change were constructed in ancient and medieval times to perform astronomical calculations. These include the Antikythera mechanism The Antikythera mechanism , is an ancient mechanical computer designed to calculate astronomical positions. It was recovered in 1900–01 from the Antikythera wreck, but its complexity and significance were not understood until decades later. It is now thought to have been built about 150–100 BC. The degree of mechanical sophistication is and the astrolabe An astrolabe is a historical astronomical instrument used by astronomers, navigators, and astrologers. Its many uses include locating and predicting the positions of the Sun, Moon, planets, and stars; determining local time (given local latitude) and vice-versa; surveying; triangulation; and to cast horoscopes. They were used in Classical from ancient Greece Ancient Greece is the civilization belonging to the period of Greek history lasting from the Archaic period of the 8th to 6th centuries BC to 146 BC and the Roman conquest of Greece after the Battle of Corinth. At the center of this time period is Classical Greece, which flourished during the 5th to 4th centuries BC, at first under Athenian (c. 150-100 BC), which are generally regarded as the first mechanical analog computers.[4] Other early versions of mechanical devices used to perform some type of calculations include the planisphere A planisphere is a star chart analog computing instrument in the form of two adjustable disks that rotate on a common pivot. It can be adjusted to display the visible stars for any time and date. It is an instrument to assist in learning how to recognize stars and constellations. The astrolabe, an instrument that has its origins in the Hellenistic and other mechanical computing devices invented by Abū Rayhān al-Bīrūnī Abū Rayḥān Muḥammad ibn Aḥmad Bīrūnī , often known as Alberuni, Al Beruni or variants, (born 5 September 973 in Kath, Khwarezm (now in Uzbekistan), died 13 December 1048 in Ghazni, today's Afghanistan) was a Persian scholar and polymath of the 11th century (c. AD 1000); the equatorium and universal latitude-independent astrolabe by Abū Ishāq Ibrāhīm al-Zarqālī Abū Isḥāq Ibrāhīm ibn Yaḥyā al-Naqqāsh al-Zarqālī , Latinized as Arzachel, was an instrument maker and one of the leading theoretical and practical astronomers of his time. Although his name is conventionally given as al-Zarqālī, it is probable that the correct form was al-Zarqālluh. He lived in Toledo in Castile, Al-Andalus (now (c. AD 1015); the astronomical analog computers of other medieval Muslim astronomers In the history of astronomy, Islamic astronomy or Arabic astronomy refers to the astronomical developments made in the Islamic world, particularly during the Islamic Golden Age , and mostly written in the Arabic language. These developments mostly took place in the Middle East, Central Asia, Al-Andalus, and North Africa, and later in the Far East and engineers; and the astronomical clock tower of Su Song (c. AD 1090) during the Song Dynasty. The "castle clock", an astronomical clock invented by Al-Jazari in 1206, is considered to be the earliest programmable analog computer.[5]
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BMC Pediatrics Pediatric IOL Calculator is a modification of SRK II using Holladay algorithm. This program attempts to predict the refraction of a pseudophakic child as he ...
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calculator A hand held non printing calculator may be used Allowable calculators may include a limited memory function that will store one to three numbers after it is turned off Scientific and graphing calculators which
Alex
ue, 24 Aug 2010 13:00:16 GM
The shocking . calculator. is an awesome office prank. Great for school and college too. Whoever uses it literally gets shocked. Watch and learn.
