 RapidCalculator  ProAlgorithms.com
This mobile computing platform for web and handheld devices performs matrix operations like multiplication/inverses; plots graphs of functions and operations on polynomials; manipulates complex numbers; and evaluates other math, science, and engineering
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 The Rappin' Mathematician  Alex Kajitani
The Rappin' Mathematician provides teachers and students with rap songs about math. Two CDs available separately or together; samples and testimonials available free on the site.
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 Ratio and Proportion  NASA Lewis Learning Technologies Project
If the ratio of boys to girls is 5 to 8 and there are 40 girls, which proportion should you use to find out the number of boys? A detailed answer is provided. From NASA's 9th Grade Math Proficiency Test.
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 Ratio  Math Forum, Ask Dr. Math Common Question
A selection of answers to questions about ratios, such as the difference between "rate" and "ratio" and "fraction"; "On a map, the scale states that 3 inches represent 125 miles...."; and "How can I write a ratio in three different ways?"
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 Ratio, Percent & Proportions (SMILE)  Rosalyn Winston, Walt Disney Magnet School
A lesson on fractions as percents, designed to teach 7th graders to find the percent of a number; find percents using proportions; calculate the weight of objects (beads) in grams given specific percents; and verify the weight of objects (beads) on a
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 Raw  DensityDesign Lab
The "missing link between spreadsheets and vector graphics," this open web app's interface lets you create custom vectorbased visualizations on top of the DataDriven Documents JavaScript (D3.js) library. Starting with delimiterseparated values in plaintext
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 Reading a Protractor or a Ruler  Math Forum, Ask Dr. Math Common Question
A selection of answers to questions about reading a protractor or a ruler, such as "What do the little lines on a ruler stand for?"
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 Readings and Poetry Selections for Mathematics in Poetry  JoAnne Growney, Bloomsburg Univ., Bloomsburg, PA; The Math Forum
Annotated bibliography for the contributed paper session, "The Scholarship of Humanistic Mathematics," AMSMAA Joint Meetings, Orlando, Florida, 1996.
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 Real World  Lesson Ideas: Math; Teachnet.Com
Activities: Buy Groceries; Plan Christmas Vacation; Credit Cards for Kids; Who's Average?; Carpet Your Classroom; Division from a Printer's Viewpoint.
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 Real World Math  Thomas J. Petra
Lessons that use Google Earth to teach math include Oil Spill Estimates and Scientific Notations; Iditarod Challenge and Typhoon Project; Four Color Map and Mazes & Labyrinths; Crop Circles and Fractal Measurement; Lunar Sports and Rockets. Each lesson
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 Real World Math Via the Internet  Wendi Fein, M.A., Heritage Online
K12 math using real world problems and data that will support interdisciplinary teaching of science, social studies, history and business. Teachers in this course take advantage of the Internet for class discussions and to access material, and prepare
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 Reason and Wonder  Michael Fenton
Blog by a Fresno (California) junior high and high school mathematics teacher. Posts, which date back to March, 2013, have included "Estimation 180 Rocks"; "Quadratics Matching Activity, Take 2"; "Solved the Student Engagement Problem Yet? Me Neither";
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 Reasoning Mind  Reasoning Mind Inc.
Reasoning Mind is a nonprofit organization. It's also a core curriculum based on programs proven successful in Russia, China, and Singapore. A Reasoning Mind classroom combines a teacher and the computer, aiming to get kids so interested in math they'll
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 Reasons for Studying (Learning and Mathematics)  Susan Bobbitt Nolen; Math Forum
In this 1988 article, "Reasons for studying: Motivational orientations and study strategies," Susan Bobbitt Nolen, of the University of Washington, argues that in order to foster meaningful learning and effective study strategies, teachers should reduce
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 Reassessing U.S. International Mathematics Performance: New Findings from the 2003 TIMSS and PISA  American Institutes for Research
"Despite a widely held belief that U.S. students do well in mathematics in grade school but decline precipitously in high school, a new study comparing the math skills of students in industrialized nations finds that U.S. students in 4th and
8th grade
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 Rebecca Newburn
Links to this California teacher's Math 7 blog, and to her professional blog, a "fusion of best teaching practices, integrating technology and increasing compassion in and outside of the classroom." See also Newburn's select compilation of explanations,
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 Rebuilding an Empire  Mike Waechter
Blog by a middle school math teacher in northern California. Posts, which date back to March, 2015, have included "The Good, The Bad and A Moment"; "NBA Desmos Scatter Plots"; and "Barbie Zip Line."
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 Recent Earthquake Teachable Moments  Incorporated Research Institutions for Seismology (IRIS)
Incorporated Research Institutions for Seismology (IRIS) is a university consortium sponsored by the National Science Foundation (NSF), dedicated to the operations of scientific facilities for the acquisition, management, and distribution of freely available
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 Recherche dans MATHS France  Académie de Toulouse
Un moteur de recherche qui scanne tous les sites académiques en mathématiques.
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 Recipes for Pi  Anna Weltman
Blog born partly "out of a mixture of enthusiasm and anger about the ways that the world learns and shares math." Posts, which date back to February, 2012, have included "Tinker, Tinker, Algebra Student"; "Beauty Is a Math Art Class"; "The Mathematics
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 The Recovering Traditionalist  Christina Tondevold
Blog by a "former middle school math teacher who learned, and taught, math the traditional way. That was until I realized that many of my students did not learn math the same way I did. So, I embarked on a journey to increase my understanding of mathematics
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 The rec.puzzles Archive
The index of the rec.puzzles archive. Puzzles are categorized by subject area and include solutions compiled from various sources and supposed to be definitive. Subjects include: analysis, arithmetic, combinatorics, competition, decision, geometry, group,
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 The rec.puzzles Archive  Massachusetts Institute of Technology (M.I.T.)
A list of puzzles, categorized by subject area, from the newsgroup rec.puzzles. Puzzles include solutions compiled from various sources, supposed to be definitive. Subjects include analysis, arithmetic, combinatorics, competition, decision, geometry,
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 Recreational Mathematics  David Eppstein, Theory Group, ICS, UC Irvine
Some Web resources for recreational math, including links to Eppstein's pages own (Number Theory, Combinatorial Game Theory, and The Geometry Junkyard) and to pages by others.
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 Rectangle Pattern Challenges  Cynthia Lanius
Examine different stges of rectangle patterns, and describe what you must do to get from one to the next. Observe the designs looking for patterns. Use the symmetry of the design to help you count. Organize your information into a table. On square grid
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 Rectangle Perimeter and Side Length  NASA Lewis Learning Technologies Project
A rectangle with a perimeter of 24 inches might have adjacent sides measuring: 6 inches and 4 inches; 11 inches and 13 inches; 9 inches and 3 inches; or, 2 inches and 12 inches? A detailed answer is provided. From NASA's 9th Grade Math Proficiency Test.
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 Rectangular Parallelepiped, Cube Formulas (Ask Dr. Math FAQ)  Math Forum
Formulas for finding the surface area and volume of a rectangular parallelepiped and a cube.
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 Recursos de Matemáticas en Internet  Flavio P.
Información buscable, dividida en categorías que contienen enlaces comentados: altas, actividades, actualización, apuntes, buscadores, congresos, debate, enlaces, Escher, fractales, historia, lista general, Olimpiadas, publicaciones,
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 Recycling Topology  Ivars Peterson (MathLand)
It's hard to miss the triangle of three bent arrows that signifies recycling. It appears in newspapers and magazines and on bottles, envelopes, cardboard cartons, and other containers. But have you noticed that there are two versions of this ubiquitous
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 Reducing/Simplifying Fractions  Math Forum, Ask Dr. Math Common Question
A selection of answers to questions about reducing and simplifying fractions, such as "How do you know when a fraction is in its simplest form?" and "What is the easiest method of reducing fractions to lowest terms?" and "Should fractions always be reduced
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 Reflections in the Why  Chris Hunter
Blog by a K–12 numeracy helping teacher in Vancouver. Posts, which date back to September, 2010, have included "Linear Functions — Concretely, Pictorially, Symbolically"; "Math Manipulative of the Month — Base Ten Blocks"; "A Linear Functions
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 Reflections of a Techie  Marsha Ratzel
Reflections "on using 21st century technologies to amplify learning," as blogged by a selfdescribed nerd who teachers middle grades math. Posts, which date back to July, 2003, have included "Finding the Little Truths of Math"; "Rational numbers need
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 Reflections on Deep Blue  Keith Devlin (Devlin's Angle)
We generally assume that the ability to play a good game of chess requires intelligence when it comes to people. Why not for chessplaying machines as well? Well, here is one argument that shows that things are not so simple. One aspect of human intelligence,
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 reflectivemaths  Dave Gale
Blog of "ideas as well as the odd resource" by an Advanced Skills Teacher (AST), SSAT Lead Practitioner and member of the TES Maths panel. Posts, which date back to December, 2010, have included "Mereside yr6 Daily Maths Challenge," "When Mathematicians
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 Regular Polygon Formulas (Ask Dr. Math FAQ)  Math Forum
Formulas for finding the area, perimeter, etc. of a regular polygon, and constructing regular polygons with compass and straightedge, in particular the pentagon.
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 Regular Polyhedra: Formulas (Ask Dr. Math FAQ)  Math Forum
Formulas for finding the surface area, perimeter, volume, etc. of regular polyhedra: tetrahedron, cube, octahedron, dodecahedron, icosahedron.
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 Religious Beliefs Made Visual: Geometry and Islam  Jane Norman, Consultant, Metropolitan Museum of Art
Although the shapes and structures are based on the geometry of Euclid and other Greek mathematicians, Islamic artists used them to create visual statements about religious ideas. A discussion of the use of geometric motifs in Islamic art, with instructions
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 REL Network
The network of ten Regional Educational Laboratories (RELs), serving geographic regions that span the nation, works to ensure that those involved in educational improvement at the local, state, and regional levels have access to the best available information
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 Remainder/Divisibility Puzzles  Math Forum, Ask Dr. Math Common Question
A selection of answers to questions about remainder and divisibility puzzles, such as "Write 1,000,000,000 as the product of two numbers, neither of which contains any zeros" and "Arrange the digits 0 to 9 such that the number formed by the first digit
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 The Remarkable Number 1/89  Robert Miner
An overview of the Fibonacci series, interesting facts about it, and a sketch of the proof of why the decimal expansion of the fraction 1/89 contains all the Fibonacci numbers expressed as a sequence of decimal fractions, a fact discovered by Cody Birsner.
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 Renaissance Learning Math Software  Renaissance Learning, Inc.
A tool for educators that provides fresh exam and worksheet questions using algorithms to generate unique new permutations each time you use it. It is designed to meet the latest NCTM assessment standards for grades 512 using performance assessment questions
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 Renato Montemurro
Libri dall'inventore delle tabelline times table: L'insegnamento della matematica nella scuola elementare (La Scuola); La matematica dalla scuola dell'infanzia alla scuola elementare (La Nuova Italia); una guida didattica per l'insegnante della scuola
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 Report to the President on the Use of Technology to Strengthen K12 Education in the United States, March 1997  President's Committee on Science and Technology
A paper by the Panel on Educational Technology. Sections include: Introduction; Potential Significance; Hardware and Infrastructure; Software, Content and Pedagogy; Teachers and Technology; Economic Considerations; Equitable Access; Research and Evaluation;
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 The Republic of Mathematics  Gary E. Davis
The Republic of Mathematics™ was founded "to promote happy and productive mathematical experiences for all learners, democratize the learning and teaching of mathematics, and help empower students and teachers in their engagement with mathematics."
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 Research for Better Schools (RBS)
An educational R&D firm serving the MidAtlantic region, currently operating the MidAtlantic Eisenhower Consortium for Mathematics and Science Education. RBS offers educational development, evaluation, technical assistance, and training services
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 Research Ideas  George Gadanidis
Disseminating math education research through performance, and studying the process and impact of research performance. Funded by the Fields Institute, Random Acts of Math brings math ideas to young children and their parents. Music videos of the Math
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 Research in Math Education  Mathematics Education at The Math Forum
Research into the learning and teaching of mathematics: methods; K12 and college undergraduate education (articles, conference sessions); bibliographies; centers; studies; special interest groups; organizations and journals.
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 Research in Practice  Ben BlumSmith
A "math education research digest" by a former teacher, private tutor, and faculty member of Bard College's Master of Arts in Teaching program who went on to pursue his doctoral degree from the Courant Institute of Mathematical Sciences at New York University.
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 Resourceaholic  Joanne Morgan
Blog of teaching ideas and resources recommended by a Key Stage 5 Coordinator in a Greater London (UK) girls' grammar school. Posts, which date back to April, 2014, have included a recurring series of "math gems" as well as "Highest Common Factor and
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 Resource Bibliography: Children's Trade Books in Math  Beth G. Newhouse, Department of Mathematics & Statictics, Arizona State University
A selected bibliography of books for kids that teach and reinforce math concepts, organized by topic: counting and number, number operations, large numbers, money, geometry, algebra, miscellaneous topics. Originally compiled by Dorothy Giroux and Denise
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