Graphing calculator
Encyclopedia
A graphing calculator (also graphics / graphic calculator) typically refers to a class of handheld calculator
Calculator
An electronic calculator is a small, portable, usually inexpensive electronic device used to perform the basic operations of arithmetic. Modern calculators are more portable than most computers, though most PDAs are comparable in size to handheld calculators.The first solid-state electronic...

s that are capable of plotting graphs, solving simultaneous equations, and performing numerous other tasks with variables. Most popular graphing calculators are therefore also programmable, allowing the user to create customized programs, typically for scientific/engineering and education applications. Due to their large displays intended for graphing, they can also accommodate several lines of text and calculations at a time. Some of the more recent graphing calculators are capable of color output, and also feature animated and interactive drawing of math plots (2D and 3D), other figures such as animated Geometry theorems, preparation of documents which can include these plots and drawings, etc. This is giving the new graphing calculators a presence even in high school courses where they were formerly disallowed. Some calculator manufacturers also offer computer software for emulating and working with handheld graphing calculators.

Graphing calculators can be sub-divided into two categories (both need the graphical display):

1. Numerical (or just graphing) Calculators - non-CAS and producing numerical results, at most represented as a fraction. In some countries, graphing calculators are not permitted in high school science tests or certain basic math tests. See examples below.

2. CAS (or symbolic) Calculators - most advanced calculators capable of producing a symbolic result (in expression or equation form), usually utilizing a Computer Algebra System (CAS
Computer algebra system
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.-Symbolic manipulations:...

). Symbolic/CAS calculators are posing a challenge to high school and undergraduate educators. They can make math easier to learn for high schoolers, provided school curriculum evolves towards this advantage. Testing based on tedious hand calculation is also being forced to evolve towards more creative testing. Such tests are often more challenging and expensive to design and can't be recycled as much, but encourage a genuine deeper appreciation of the art of mathematics and critiqueing a fallacy. CAS calculators are therefore usually permitted only in select advanced math or calculus tests, thereby being more of a classroom learning tool for many users who then switch to a permitted and speedy numerical non-CAS graphing or scientific calculator for tests and exams.

Many graphing calculators can be attached to devices like electronic thermometers, pH gauges, weather instruments, decibel and light meters, accelerometer
Accelerometer
An accelerometer is a device that measures proper acceleration, also called the four-acceleration. This is not necessarily the same as the coordinate acceleration , but is rather the type of acceleration associated with the phenomenon of weight experienced by a test mass that resides in the frame...

s, and other sensors and therefore function as data loggers, as well as WiFi or other communication modules for monitoring, polling and interaction with the teacher. Student laboratory exercises with data from such devices enhances learning of math, especially statistics and mechanics.

Since graphing calculators are usually readily user-programmable, such calculators are also widely used for gaming purposes, with a sizable body of user-created game software on most popular platforms. Even though handheld gaming devices fall in a similar price range, graphing calculators offer superior math programming capability for math based games. However, for developers and advanced users like researchers, analysts and gamers, 3rd party software development involving firmware mods, whether for powerful gaming or exploiting capabilities beyond the published data sheet and programming language, is a contentious issue with manufacturers and education authorities as it might incite unfair calculator use during standardized high school and college tests where these devices are targeted. Graduate (Masters) students and researchers have turned to advanced Computer Aided Math software such as that listed below, for learning as well as experimenting, with the graphing calculator which was once seen as the hallmark of the white-coated scientist, gradually being relegated to adjunct status or for limited exam taking.

History

Casio
Casio
is a multinational electronic devices manufacturing company founded in 1946, with its headquarters in Shibuya, Tokyo, Japan. Casio is best known for its electronic products, such as calculators, audio equipment, PDAs, cameras, musical instruments, and watches...

 produced the world's first graphics calculator, the fx-7000G
Casio fx-7000G
The Casio fx-7000G is notable for being the world's first graphing calculator.It came with 422 bytes of memory and it was possible to store up to ten programs in 10 program slots. 422 bytes is not much by today's standards, but with its heavily tokenised programming language, programs performing...

, in 1985. After Casio, Hewlett Packard followed shortly in the form of the HP-28C. This was followed by the HP-28S (1988), HP-48SX (1990), HP-48S (1991), and many other models. Recent models like the HP 50g (2006), feature a computer algebra system
Computer algebra system
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.-Symbolic manipulations:...

 (CAS) capable of manipulating symbolic expressions and analytic solving. An unusual and powerful CAS "calculator" is the now obsolete year 2001 Casio Cassiopeia A10 and A11 (flip top) stylus operated PDAs which actually ran the Maple V symbolic engine. The HP-28 and -48 range were primarily meant for the professional science/engineering markets; the HP-38/39/40 were sold in the high school/college educational market; while the HP-49 series cater to both educational and professional customers of all levels. The HP series of graphing calculators is best known for its Reverse Polish notation
Reverse Polish notation
Reverse Polish notation is a mathematical notation wherein every operator follows all of its operands, in contrast to Polish notation, which puts the operator in the prefix position. It is also known as Postfix notation and is parenthesis-free as long as operator arities are fixed...

 interface, although the HP-49 introduced a standard expression entry interface as well.

Texas Instruments has produced graphing calculators since 1990, the oldest of which was the TI-81. Some of the newer calculators are similar, with the addition of more memory, faster processors, and USB connection such as the TI-82, TI-83 series, and TI-84 series. Other models, designed to be appropriate for students 10–14 years of age, are the TI-80 and TI-73. Other TI graphing calculators have been designed to be appropriate for calculus, namely the TI-85, TI-86, TI-89 series, and TI-92 series (TI-92, TI-92 Plus, and Voyage 200). TI offers a CAS on the TI-89, TI-Nspire CAS and TI-92 series models with the TI-92 series featuring a QWERTY keypad. TI calculators are targeted specifically to the educational market, but are also widely available to the general public.

Graphing calculators are also manufactured by Sharp but they do not have the online communities, user-websites and collections of programs like the other brands.

Graphing calculators in schools

  • North America – high school mathematics teachers allow and even encourage their students to use graphing calculators in class. In some cases (especially in calculus
    Calculus
    Calculus is a branch of mathematics focused on limits, functions, derivatives, integrals, and infinite series. This subject constitutes a major part of modern mathematics education. It has two major branches, differential calculus and integral calculus, which are related by the fundamental theorem...

     courses) they are required. Some of them are banned in certain classes such as chemistry
    Chemistry
    Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....

     or physics
    Physics
    Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

     due to their capacity to contain full periodic table
    Periodic table
    The periodic table of the chemical elements is a tabular display of the 118 known chemical elements organized by selected properties of their atomic structures. Elements are presented by increasing atomic number, the number of protons in an atom's atomic nucleus...

    s.
  • College Board
    College Board
    The College Board is a membership association in the United States that was formed in 1900 as the College Entrance Examination Board . It is composed of more than 5,900 schools, colleges, universities and other educational organizations. It sells standardized tests used by academically oriented...

     of the United States
    – permits the use of most graphing or CAS
    Computer algebra system
    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.-Symbolic manipulations:...

     calculators that do not have a QWERTY
    QWERTY
    QWERTY is the most common modern-day keyboard layout. The name comes from the first six letters appearing in the topleft letter row of the keyboard, read left to right: Q-W-E-R-T-Y. The QWERTY design is based on a layout created for the Sholes and Glidden typewriter and sold to Remington in the...

    -style keyboard for parts of its AP and SAT
    SAT
    The SAT Reasoning Test is a standardized test for college admissions in the United States. The SAT is owned, published, and developed by the College Board, a nonprofit organization in the United States. It was formerly developed, published, and scored by the Educational Testing Service which still...

     exams, but IB schools do not permit the use of calculators with computer algebra systems on its exams.
  • United Kingdom – a graphics calculator is allowed for most A-level
    GCE Advanced Level
    The Advanced Level General Certificate of Education, commonly referred to as an A-level, is a qualification offered by education institutions in England, Northern Ireland, Wales, Cameroon, and the Cayman Islands...

     maths courses, however they are not required and as the exams are designed to be broadly 'calculator neutral'. Similarly, for some GCSE maths exams, students are permitted to use graphical calculators, however their use at GCSE is not widespread with cost being a likely factor. The use of CAS
    Computer algebra system
    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.-Symbolic manipulations:...

     is not allowed for either A-level
    GCE Advanced Level
    The Advanced Level General Certificate of Education, commonly referred to as an A-level, is a qualification offered by education institutions in England, Northern Ireland, Wales, Cameroon, and the Cayman Islands...

     or GCSE
  • Finland and Slovenia – and certain other countries, it is forbidden to use calculators with symbolic calculation (CAS
    Computer algebra system
    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.-Symbolic manipulations:...

    ) or 3D graphics features in the matriculation exam. This will change in the case of Finland, however, as symbolic calculators will be allowed from spring 2012 onwards.
  • Norway – calculators with wireless communication capabilities, such as IR
    Infrared
    Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

     links, have been banned at some technical universities.
  • Australia – policies vary from state to state.
  • Victoria, Australia – the VCE
    VCE
    VCE could refer to:* Victorian Certificate of Education, Year 11 and 12 qualification in Victoria, Australia* Vocational Certificate of Education, a Further Education qualification in the United Kingdom...

     specifies approved calculators as applicable for its mathematics exams. For Further Mathematics
    Further Mathematics
    Further Mathematics is the title given to a number of advanced secondary mathematics courses. Higher and Further Mathematics may also refer to any of several advanced mathematics courses at many institutions....

     an approved graphics calculator (for example TI-83/84, Casio 9860, HP-39G
    HP-39g series
    HP-39g series calculators are the successors of HP-38G.There are five calculators in the 39 series of HP graphing calculators. These calculators have algebraic entry modes, and can perform numeric analysis together with varying degrees of symbolic calculation...

    ) or CAS (for example TI-89, Classpad 300, HP-40G
    HP-40G
    The HP-40G is an algebraic entry only graphing calculator from HP. Based on the HP-38G design, numerous firmware improvements and the inclusion of a CAS made this a very capable math platform....

    ) can be used. Mathematical Methods and Mathematical Methods CAS have a common technology free examination consisting of short answer and some extended answer questions. They also each have a technology assumed access examination consisting of extended response and multiple choice questions: a graphics calculator is the assumed technology for Mathematical Methods and a CAS for Mathematical Methods CAS. These two exams have substantial material in common but also some distinctive questions. Specialist Mathematics has a technology free examination and a technology assumed access examination where either an approved graphics calculator or CAS may be used. Calculator memories are not required to be cleared. In subjects like Physics and Chemistry, students are only allowed a standard scientific calculator.
  • Western Australia – all tertiary entrance examinations in Mathematics involve a calculator section which assume the student has a graphics calculator; CAS enabled calculators are also permitted. In subjects such as Physics, Chemistry and Accounting only non programmable calculators are permitted.
  • New South Wales – graphics calculators are allowed for the General Mathematics Higher School Certificate exam, but disallowed in the higher level Mathematics courses.
  • New Zealand – calculators identified as having high-level algebraic manipulation capability are prohibited in NCEA
    National Certificate of Educational Achievement
    The National Certificate of Educational Achievement is, since 2004, the official secondary school qualification in New Zealand.It has three levels, corresponding to the levels within the National Qualifications Framework, and these are generally studied in each of the three final years of...

     examinations unless specifically allowed by a standard or subject prescription. This includes calculators such as the TI-89 series http://www.nzqa.govt.nz/ncea/acrp/secondary/4/47.html.
  • Turkey – any type of calculator whatsoever is prohibited in all primary and high schools except the IB and American schools.
  • Singapore – graphing calculators are used in junior colleges; it is required in the Mathematics paper of the GCE 'A' Levels, and most schools use the TI-84 Plus or TI-84 Plus Silver Edition.
  • Netherlands – high school students are obliged to use graphing calculators during tests and exams in their final three years. Most students use the TI-83 Plus or TI-84 Plus, but other graphing calculators are allowed, including the Casio CFX-9860G and HP-39G.

Programming

Most graphing calculators, as well as some non-graphing scientific and programmer's calculators can be programmed to automate complex and frequently used series of calculations and those inaccessible from the keyboard.

The actual programming can often be done on a computer then later uploaded to the calculators. The most common tools for this include the PC link cable and software for the given calculator, configurable text editors or hex editors, and specialized programming tools such as the below-mentioned implementation of various languages on the computer side.

Earlier calculators stored programs on magnetic cards and the like; increased memory capacity has made storage on the calculator the most common implementation. Some of the newer machines can also use memory cards.

Many calculators, such as earlier TI graphing and scientific calculators will tokenize the code for a program or function, using ISO 8859 type character codes for the statements and other programming elements. The TI-92 Plus and many HP calculators read the code much like computers do and they have functions such as Chr$, Chr, Char, Asc, and the like in Basic (sometimes renamed) in addition to using somewhat modified or unmodified versions of 7-bit, 8-bit or 9-bit ISO 8859-derived character sets and other character sets running from of values of 0 to 127 (07F hex), 255 (0FF hex), or 511 (1FF hex) -- and many of them have a tool similar to the Character Map on Windows.

Three websites with extensive programming information are www.ticalc.org, www.hpcalc.org, and www.casiocalc.org. The official sites of the manufacturers and of other people like professors & teachers, students, statisticians, scientists, and organizations like university business and computer science departments, SourceForge, and the 27. November Spreadsheet Macro Programming Club are also useful. A broad array of third-party software including 3D function graphing tools, web browsers, chat, email and NNTP clients, telnet/SSH, spreadsheets, word processors, sound & graphics tools, network tools, and programming tools can be located on the internet.

A cable and/or IrDA transceiver connecting the calculator to a computer make the process easier and expands other possibilities such as on-board spreadsheet, database, graphics, and word processing programs. The second option is being able to code the programs on board the calculator itself. This option is facilitated by the inclusion of full-screen text editors and other programming tools in the default feature set of the calculator or as optional items. Some calculators have QWERTY keyboards and others can be attached to an external keyboard which can be close to the size of a regular 102-key computer keyboard. Programming is a major use for the software and cables used to connect calculators to computers, other calculators &c.

The most common programming languages used for calculators are similar to keystroke-macro languages and variants of BASIC
BASIC
BASIC is a family of general-purpose, high-level programming languages whose design philosophy emphasizes ease of use - the name is an acronym from Beginner's All-purpose Symbolic Instruction Code....

. The latter can have a large feature set -- approaching that of Basic as found in computers -- including character and string manipulation, advanced conditional and branching statements, sound, graphics, and more including, of course, the huge spectrum of mathematical, string, bit-manipulation, number base, I/O, and graphics functions built into the machine.

Languages for programming calculators fall into all of the main groups, i.e. machine code, low-level, mid-level, high-level languages for systems and application programming, scripting, macro, and glue languages, procedural, functional, imperative &. Object-Oriented Programming can be achieved in some cases.

Most calculators capable to being connected to a computer can be programmed in assembly language and machine code, although on some calculators this is only possible through using exploits. The most common assembly and machine languages are for the purpose-designed, TMS9900, SH3, Zilog Z-80, and various Motorola chips (e.g. the modified 68000) which serve as the Central Processing Units of the machines. At least one machine in development may have a conventional 80*86 series, RISC, or purpose-built Intel chip. All of the above chips are modified to some extent from their use elsewhere. Some manufacturers do not document and even mildly discourage the assembly language programming of their machines because they must programmed in this way by putting together the program on the PC and then forcing it into the calculator by various improvised methods.

Other on-board programming languages include purpose-made languages, variants of Eiffel
Eiffel (programming language)
Eiffel is an ISO-standardized, object-oriented programming language designed by Bertrand Meyer and Eiffel Software. The design of the language is closely connected with the Eiffel programming method...

, Forth, and Lisp, and Command Script facilities which are similar in function to batch/shell programming and other glue languages on computers but generally not as full featured. Ports of other languages like BBC Basic
BBC BASIC
BBC BASIC is a programming language, developed in 1981 as a native programming language for the MOS Technology 6502 based Acorn BBC Micro home/personal computer, mainly by Sophie Wilson. It is a version of the BASIC programming language adapted for a U.K...

 and development of on-board interpreters for Fortran
Fortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...

, Rexx
REXX
REXX is an interpreted programming language that was developed at IBM. It is a structured high-level programming language that was designed to be both easy to learn and easy to read...

, Awk, Perl
Perl
Perl is a high-level, general-purpose, interpreted, dynamic programming language. Perl was originally developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions and become widely popular...

, Unix shells (ksh
Korn shell
The Korn shell is a Unix shell which was developed by David Korn in the early 1980s and announced at USENIX on July 14, 1983. Other early contributors were AT&T Bell Labs developers Mike Veach, who wrote the emacs code, and Pat Sullivan, who wrote the vi code...

, sh
Bourne shell
The Bourne shell, or sh, was the default Unix shell of Unix Version 7 and most Unix-like systems continue to have /bin/sh - which will be the Bourne shell, or a symbolic link or hard link to a compatible shell - even when more modern shells are used by most users.Developed by Stephen Bourne at AT&T...

, bash, csh
C shell
The C shell is a Unix shell that was created by Bill Joy while a graduate student at University of California, Berkeley in the late 1970s. It has been distributed widely, beginning with the 2BSD release of the BSD Unix system that Joy began distributing in 1978...

, zsh, tcsh
Tcsh
tcsh is a Unix shell based on and compatible with the C shell . It is essentially the C shell with programmable command line completion, command-line editing, and a few other features.-History:...

 &c.), other shells (DOS/Win95, OS/2, and WinNT/2000 shells as well as the related 4Dos
4DOS
4DOS is a command line interpreter by JP Software, designed to replace the default command interpreter COMMAND.COM in DOS and Windows 95/98/Me. The 4DOS family of programs are meant to replace the default command processor. 4OS2 and 4NT replace CMD.EXE in OS/2 and Windows NT respectively...

, 4NT
4NT
Take Command Console , formerly known as 4DOS for Windows NT and 4NT, is a command line interpreter by JP Software, designed as a substitute for the default command interpreter in Microsoft Windows...

 and 4OS2 as well as DCL
DCL
- Organizations :* Detroit College of Law, now known as Michigan State University College of Law* Data Connection Ltd, see Metaswitch* Disney Cruise Line, a cruise line company * Distillers Company Limited, a producer of spirits...

), Cobol
COBOL
COBOL is one of the oldest programming languages. Its name is an acronym for COmmon Business-Oriented Language, defining its primary domain in business, finance, and administrative systems for companies and governments....

, C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....

, Python
Python (programming language)
Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python claims to "[combine] remarkable power with very clear syntax", and its standard library is large and comprehensive...

, Tcl
Tcl
Tcl is a scripting language created by John Ousterhout. Originally "born out of frustration", according to the author, with programmers devising their own languages intended to be embedded into applications, Tcl gained acceptance on its own...

, Pascal
Pascal (programming language)
Pascal is an influential imperative and procedural programming language, designed in 1968/9 and published in 1970 by Niklaus Wirth as a small and efficient language intended to encourage good programming practices using structured programming and data structuring.A derivative known as Object Pascal...

, Delphi
Object Pascal
Object Pascal refers to a branch of object-oriented derivatives of Pascal, mostly known as the primary programming language of Embarcadero Delphi.-Early history at Apple:...

, ALGOL
ALGOL
ALGOL is a family of imperative computer programming languages originally developed in the mid 1950s which greatly influenced many other languages and became the de facto way algorithms were described in textbooks and academic works for almost the next 30 years...

, and other languages are at various levels of development.

Some calculators, especially those with other PDA-like functions have actual operating systems including the TI proprietary OS for its more recent machines, MS-DOS, Windows CE, and rarely Windows NT 4.0 Embedded et seq, and Linux. Experiments with the TI-89
TI-89 series
The TI-89 and the TI-89 Titanium are graphing calculators developed by Texas Instruments. They are differentiated from most other TI graphing calculators by their computer algebra system, which allows symbolic manipulation of algebraic expressions...

, 92, 92+ and Voyage 200
TI-92 series
The TI-92 series of graphing calculators are a line of calculators produced by Texas Instruments. They include: the TI-92 , the TI-92 Plus , and the Voyage 200 . The design of these relatively large calculators includes a QWERTY keyboard...

 machines show the possibility of installing some variants of other systems such as a chopped-down variant of CP/M, an operating system which has been used for portable devices in the past.

Tools which allow for programming the calculators in C/C++ and possibly Fortran and assembly language are used on the computer side, such as HPgcc, TIgcc and others. Flash memory is another means of conveyance of information to and from the calculator.

The on-board Basic variants in TI graphing calculators and the languages available on HP 48 type calculators
HP-48 series
The HP-48 is a series of graphing calculators using Reverse Polish notation and the RPL programming language, produced by Hewlett-Packard from 1990 until 2003. The series include the HP-48S, HP-48SX, HP-48G, HP-48GX, and HP-48G+, the G models being expanded and improved versions of the S models...

 can be used for rapid prototyping by developers, professors, and students, often when a computer is not close at hand.

Most graphing calculators have on-board spreadsheets which usually integrate with Microsoft Excel on the computer side. At this time, spreadsheets with macro and other automation facilities on the calculator side are not on the market. In some cases, the list, matrix, and data grid facilities can be combined with the native programming language of the calculator to have the effect of a macro and scripting enabled spreadsheet.

See also

  • Scientific calculator
    Scientific calculator
    A scientific calculator is a type of electronic calculator, usually but not always handheld, designed to calculate problems in science, engineering, and mathematics...

  • Calculator gaming
    Calculator gaming
    Calculator gaming is the phenomenon of programming and playing games on programmable calculators, especially graphing calculators. It is largely a pastime of high school and college students, who generally are required to use such powerful calculators in advanced mathematics classes; as a result,...

  • GraphCalc
    GraphCalc
    GraphCalc is an open source and GPLed computer program that runs in Microsoft Windows and Linux that provides the functionality of a graphing calculator....

  • Personal Digital Assistant
    Personal digital assistant
    A personal digital assistant , also known as a palmtop computer, or personal data assistant, is a mobile device that functions as a personal information manager. Current PDAs often have the ability to connect to the Internet...

  • Programmable calculator
    Programmable calculator
    Programmable calculators are calculators that can automatically carry out a sequence of operations under control of a stored program, much like a computer. The first programmable calculators such as the IBM CPC used punched cards or other media for program storage...

  • Casio graphic calculators
    Casio graphic calculators
    Graphic calculators made by Casio include the touchscreen Classpad 300 as well as the models with traditional buttons which can be divided into two main generations listed below.Casio produced the world's first graphing calculator, the fx-7000G....


Further reading

  • Dick, Thomas P. (1996). Much More than a Toy. Graphing Calculators in Secondary school Calculus. In P. Gómez and B. Waits (Eds.), Roles of Calculators in the Classroom pp 31–46). Una Empresa Docente.
  • Ellington, A. J. (2003). A meta-analysis of the effects of calculators on students' achievement and attitude levels in precollege mathematics classes. Journal for Research in Mathematics Education. 34(5), 433-463.
  • Heller, J. L., Curtis, D. A., Jaffe, R., & Verboncoeur, C. J. (2005). Impact of handheld graphing calculator use on student achievement in algebra 1: Heller Research Associates.
  • Khoju, M., Jaciw, A., & Miller, G. I. (2005). Effectiveness of graphing calculators in K-12 mathematics achievement: A systematic review. Palo Alto, CA: Empirical Education, Inc.
  • National Center for Education Statistics. (2001). The nation's report card: Mathematics 2000. (No. NCES 2001-571). Washington DC: U.S. Department of Education.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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