MetaFilter posts tagged with arithmetic
http://www.metafilter.com/tags/arithmetic
Posts tagged with 'arithmetic' at MetaFilter.Thu, 20 Aug 2015 08:25:27 -0800Thu, 20 Aug 2015 08:25:27 -0800en-ushttp://blogs.law.harvard.edu/tech/rss60Can you add faster than a 5 year old
http://www.metafilter.com/152276/Can%2Dyou%2Dadd%2Dfaster%2Dthan%2Da%2D5%2Dyear%2Dold
CMA is a "brain development program designed to develop higher learning capability and aims to promote mental arithmetic, enhance memory, boost creativity, and increase focus using the principle of Abacus". <a href="https://www.youtube.com/watch?v=MYUcsqx5Bh4">Watch some kids from The Philippines calculates in seconds, using their fingers.</a> (SLYT) tag:metafilter.com,2015:site.152276Thu, 20 Aug 2015 08:25:27 -0800growabrain"Their little heads are exploding"
http://www.metafilter.com/150636/Their%2Dlittle%2Dheads%2Dare%2Dexploding
<a href="http://bit-player.org/2015/mrs-nguyens-prestidigitation">Mrs. Nguyen's Prestidigitation</a> <i>From a set of 1 through 9 playing cards, I draw five cards and get cards showing 8, 4, 2, 7, and 5. I ask my 6th graders to make a 3-digit number and a 2-digit number that would yield the greatest product...</i> and somehow we end up with lacing diagrams and Python. (<a href="http://fawnnguyen.com/multiplication-finding-the-greatest-product/">The original post on Fawn Nguyen's blog</a>) tag:metafilter.com,2015:site.150636Mon, 22 Jun 2015 06:45:32 -0800Wolfdog3Blue1Brown: Reminding the world that math makes sense
http://www.metafilter.com/150242/3Blue1Brown%2DReminding%2Dthe%2Dworld%2Dthat%2Dmath%2Dmakes%2Dsense
<a href="https://www.youtube.com/watch?v=F_0yfvm0UoU">Understanding e to the pi i</a> - "<a href="http://www.3blue1brown.com/s/HowToThinkAboutExponentials.pdf">An intuitive explanation</a> as to why <a href="http://www.bbc.co.uk/programmes/b04hz49f" title="Melvyn Bragg and his guests discuss Euler's number, also known as e. First discovered in the seventeenth century by the Swiss mathematician Jacob Bernoulli when he was studying compound interest, e is now recognised as one of the most important and interesting numbers in mathematics. Roughly equal to 2.718, e is useful in studying many everyday situations, from personal savings to epidemics. It also features in Euler's Identity, sometimes described as the most beautiful equation ever written. With: Colva Roney-Dougal, Reader in Pure Mathematics at the University of St Andrews; June Barrow-Green, Senior Lecturer in the History of Maths at the Open University; and Vicky Neale, Whitehead Lecturer at the Mathematical Institute and Balliol College at the University of Oxford.">e</a> to the <a href="http://www.bbc.co.uk/programmes/p004y291" title="Melvyn Bragg and guests discuss the history of the most detailed number in nature. In the Bible's description of Solomon's temple it comes out as three, Archimedes calculated it to the equivalent of 14 decimal places and today's super computers have defined it with an extraordinary degree of accuracy to its first 1.4 trillion digits. It is the longest number in nature and we only need its first 32 figures to calculate the size of the known universe within the accuracy of one proton. We are talking about Pi, 3.14159 etc, the number which describes the ratio of a circle's diameter to its circumference. How has something so commonplace in nature been such a challenge for maths? And what does the oddly ubiquitous nature of Pi tell us about the hidden complexities of our world? With: Robert Kaplan, co-founder of the Maths Circle at Harvard University; Eleanor Robson, Lecturer in the Department of History and Philosophy of Science at Cambridge University; and Ian Stewart, Professor of Mathematics at the University of Warwick.">pi</a> <a href="http://www.bbc.co.uk/programmes/b00tt6b2" title="Melvyn Bragg and his guests discuss imaginary numbers. In the sixteenth century, a group of mathematicians in Bologna found a solution to a problem that had puzzled generations before them: a completely new kind of number. For more than a century this discovery was greeted with such scepticism that the great French thinker Rene Descartes dismissed it as an 'imaginary' number. The name stuck - but so did the numbers. Long dismissed as useless or even fictitious, the imaginary number i and its properties were first explored seriously in the eighteenth century. Today the imaginary numbers are in daily use by engineers, and are vital to our understanding of phenomena including electricity and radio waves. With: Marcus du Sautoy, Professor of Mathematics at Oxford University; Ian Stewart, Emeritus Professor of Mathematics at the University of Warwick; and Caroline Series, Professor of Mathematics at the University of Warwick.">i</a> equals -1 <a href="https://www.youtube.com/watch?v=1rVHLZm5Aho">without a hint</a> of calculus. This is <a href="https://www.youtube.com/watch?v=zLzLxVeqdQg">not your usual</a> Taylor series nonsense." (<a href="https://twitter.com/stevenstrogatz/status/604653212214292481" title="''A star is born.''">via</a> <a href="https://twitter.com/Noahpinion/status/604679198259580928" title="''Best geek video I've seen all week.''">via</a>; <a href="http://www.reddit.com/r/math/comments/2xzzk0/nontaylorseries_explanation_for_eulers_formula/">reddit</a>; <a href="http://www.metafilter.com/89918/Math-is-beautiful">previously</a>) <a href="https://www.youtube.com/channel/UCYO_jab_esuFRV4b17AJtAw">More videos from 3Blue1Brown</a>: "<a href="http://www.3blue1brown.com/">3Blue1Brown</a> is some combination of math and entertainment, depending on your disposition. The goal is for explanations to be <a href="http://www.3blue1brown.com/about/" title="''When the tool I am building for animations becomes something besides a jumble of Python and Duct tape, I'll make it publicly available so that anyone can use it to easily illustrate their own explanations.''">driven by animations</a>, for difficult problems to be made simple with changes in perspective, and for philosophizing to be limited to the brevity and semantic constraints of silly poetry. Basically, math sits in <a href="https://plus.google.com/117663015413546257905/posts/QAhMH35LThk">an ivory tower it built itself out of</a> jargon and impossibly long sequences of (seemingly) logical steps, and I would like to take it out for a walk to <a href="http://wordplay.blogs.nytimes.com/2015/03/09/%CF%80/">meet everyone</a>." tag:metafilter.com,2015:site.150242Sat, 06 Jun 2015 11:42:18 -0800kliulessArithmeticfilter
http://www.metafilter.com/146474/Arithmeticfilter
<a href="http://www.momonix.com/calc/">Nothing but an endless supply of mental arithmetic problems.</a> Five levels of difficulty, from "10 - 6" to "√370881." You can find slightly more granular training <a href="http://windhoff.net/mental_arithmetic/#Addition">here</a>. See <a href="http://en.wikipedia.org/wiki/Mental_calculation">Wikipedia</a> for a survey of mental methods, or read <a href="http://www-history.mcs.st-and.ac.uk/HistTopics/Mental_arithmetic.html">A.C. Aitken's</a> <a href="http://stepanov.lk.net/mnemo/aitkene.html">explanation</a> of his Art of Calculation. tag:metafilter.com,2015:site.146474Mon, 26 Jan 2015 08:41:53 -0800IridicThe one that is the smaller is the larger
http://www.metafilter.com/137307/The%2Done%2Dthat%2Dis%2Dthe%2Dsmaller%2Dis%2Dthe%2Dlarger
<a href="http://www.inference.phy.cam.ac.uk/sanjoy/benezet/three.html">The Teaching of Arithmetic: The Story of an experiment.</a> <i>In the fall of 1929 I made up my mind to try the experiment of abandoning all formal instruction in arithmetic below the seventh grade and concentrating on teaching the children to read, to reason, and to recite - my new Three R's. And by reciting I did not mean giving back, verbatim, the words of the teacher or of the textbook. I meant speaking the English language. I picked out five rooms - three third grades, one combining the third and fourth grades, and one fifth grade. I asked the teachers if they would be willing to try the experiment.</i> tag:metafilter.com,2014:site.137307Sat, 08 Mar 2014 07:55:25 -0800WolfdogHow can nothing can be something?
http://www.metafilter.com/136440/How%2Dcan%2Dnothing%2Dcan%2Dbe%2Dsomething
While<a href="http://www.storyofmathematics.com/indian_brahmagupta.html"> the concept</a> of shunya or "<a href="https://en.wikipedia.org/wiki/0_%28number%29">zero</a>", both as <a href="http://mathforum.org/library/drmath/view/52566.html">place holder</a> in the <a href="http://www2.mae.ufl.edu/~uhk/DECIMAL-SYSTEM.pdf">decimal system</a> and as "<a href="https://en.wikipedia.org/wiki/%C5%9A%C5%ABnyat%C4%81#Etymology">null</a>" or "<a href="http://scienceblogs.com/startswithabang/2011/08/16/the-physics-of-nothing-the-phi/">nothingness</a>" has been historically <a href="http://www-history.mcs.st-and.ac.uk/HistTopics/Zero.html">attributed</a> to the Indian <a href="https://en.wikipedia.org/wiki/Aryabhata">mathematician</a>/astronomer <a href="http://www-history.mcs.st-andrews.ac.uk/Mathematicians/Aryabhata_I.html">Aryabhata</a>, it <a href="http://www-history.mcs.st-and.ac.uk/Biographies/Aryabhata_I.html">was</a> when I went to search <a href="http://www.sid.ir/en/VEWSSID/J_pdf/12392000601.pdf">for its</a> history and<a href="http://historyofislam.com/contents/the-classical-period/al-khwarizmi/"> impact</a> that <a href="http://www.pantaneto.co.uk/issue5/arsham.htm">whole new world</a> was revealed. From <a href="http://www.ams.org/samplings/feature-column/fcarc-india-zero">culture</a> and <a href="http://www.dnaindia.com/lifestyle/report-understanding-zero-through-history-art-culture-1905922">art</a> to <a href="http://www.buddhanet.net/e-learning/history/b3schmah.htm">spiritual practice</a>, the <a href="http://www.speakingtree.in/spiritual-articles/science-of-spirituality/shunya-or-void-in-classical-music">concept</a> of zero has <a href="http://www.theguardian.com/science/alexs-adventures-in-numberland/2013/oct/07/mathematics1">captured</a> the <a href="http://www.thefuschiatree.com/219/fullview">imagination</a> of many <a href="http://www.hindupedia.com/en/Mathematics_of_the_Vedas">throughout the ages</a>. Books <a href="http://www.scientificamerican.com/article/history-of-zero/">have</a> been written, its origins <a href="http://arxiv.org/ftp/arxiv/papers/0707/0707.3579.pdf">debated</a> while the etymology <a href="http://yaleglobal.yale.edu/about/zero.jsp">of the word</a> itself sometimes replaces understanding. From a disconcerting concept of <a href="http://shunyarevolution.wordpress.com/2012/03/05/the-trinity-of-void-by-gwendolyn-toynton/">nothingness</a> to the <a href="https://en.wikipedia.org/wiki/History_of_Google#Name">ubiquitous misspelling</a> of the one followed by a hundred zeros, Shunya today is more than just the<a href="http://search.dilbert.com/comic/Concept%20Of%20Zero"> gaping void</a> it originally represented. tag:metafilter.com,2014:site.136440Fri, 07 Feb 2014 13:33:32 -0800infiniA Compassionate "Human Computer", RIP
http://www.metafilter.com/127308/A%2DCompassionate%2DHuman%2DComputer%2DRIP
<a href="http://blogs.smithsonianmag.com/smartnews/2013/04/math-prodigy-shakuntala-devi-the-human-computer-dies-at-83/">Shakuntala Devi</a>, the Indian "human computer," passed away on Sunday. The NY Times first did<a href="https://docs.google.com/file/d/0B1oJaHH3YrMSUThHalhIekZBTFU/edit"> a profile</a> on her when she visited the US in 1976, during which she computed the cube root of a 9 digit integer in her head, but could not remember that she had been to the US once before -- over 20 years prior. <a href="http://www.thocp.net/biographies/bemer_bob.htm">Bob Bemer</a> (inventor of the Escape key <small><a href="http://www.metafilter.com/120629/Thank-you-Mr-Bemer">previously</a></small>) <a href="http://www.bobbemer.com/DEVI.HTM">remembers meeting her</a> in 1953 on the TV show <em>You Asked For It</em> (which had previously featured <a href="http://archive.org/details/MiscEpisodeOfyouAskedForIt6">a race between an abacus and a calculator</a>). Psychologist Arthur Jensen (who did <a href="http://en.wikipedia.org/wiki/Arthur_Jensen"> controversial research</a> on race and IQ) wrote <a href="http://stepanov.lk.net/mnemo/jensen.html"> a paper on Shakuntala's exceptional ability</a> in 1990. Shakuntala made her living as an astrologer and authored numerous books mostly on mathematical puzzles and tricks, but also <em>The World of Homosexuals</em> (1977), one of the earliest ethnographic studies of gay people in India. Specifically about gays in her hometown of Bangalore, Shakuntala called for "<a href="http://intersections.anu.edu.au/issue14/chatterjee_review.html">not only the decriminalisation of homosexuality in India</a>, but also its 'full and complete acceptance' by the heterosexual population so that the Indian homosexual may lead a dignified and secure life." tag:metafilter.com,2013:site.127308Tue, 23 Apr 2013 10:49:14 -0800blueflyComputerized Math, Formal Proofs and Alternative Logic
http://www.metafilter.com/126041/Computerized%2DMath%2DFormal%2DProofs%2Dandamp%2DAlternative%2DLogic
<a href="http://www.wired.com/wiredscience/2013/03/computers-and-math/all/">Using computer systems for doing mathematical proofs</a> - "With the proliferation of <a href="http://en.wikipedia.org/wiki/Computer-assisted_proof">computer-assisted proofs</a> that are all but impossible to check by hand, Hales thinks computers must become the judge." <blockquote>Three years ago, Vladimir Voevodsky, one of the organizers of a new program on the foundations of mathematics at the Institute for Advanced Study in Princeton, N.J., discovered that a formal logic system that was developed by computer scientists, called "<a href="http://en.wikipedia.org/wiki/Type_theory">type theory</a>" could be used to re-create the entire mathematical universe from scratch. Type theory is consistent with the mathematical axioms, but couched in the language of computers. Voevodsky believes this alternative way to formalize mathematics, which he has renamed the <a href="http://video.ias.edu/univalent/voevodsky">univalent foundations of mathematics</a>, will streamline the process of formal theorem proving. Voevodsky and his team are adapting a <a href="https://plus.google.com/u/0/117663015413546257905/posts/4BZRibN6iKQ">program named Coq</a>, which was designed to formally verify computer algorithms, for use in abstract mathematics.</blockquote>
also btw, speaking of mathematical revolutions, from a historical perspective, check out <a href="http://www.scientificamerican.com/article.cfm?id=the-man-of-numbers-fibona&print=true">The Man of Numbers: Fibonacci's Arithmetic Revolution</a> - "Before the 13th century Europeans used Roman numerals to do arithmetic. Leonardo of Pisa, better known today as Fibonacci, is largely responsible for the adoption of the Hindu–Arabic numeral system in Europe, which revolutionized not only mathematics but commerce and trade as well. How did the system spread from the Arab world to Europe, and what would our lives be without it?" tag:metafilter.com,2013:site.126041Sat, 16 Mar 2013 15:33:01 -0800kliulessThe ternary calculating machine of Thomas Fowler
http://www.metafilter.com/116378/The%2Dternary%2Dcalculating%2Dmachine%2Dof%2DThomas%2DFowler
<a href="http://www.mortati.com/glusker/fowler/index.htm">The ternary calculating machine</a> of Thomas Fowler. And <a href="http://www.mortati.com/glusker/elecmech/index.htm">electromechanical calculating machines</a> from the 1960s. tag:metafilter.com,2012:site.116378Mon, 28 May 2012 06:17:08 -0800WolfdogMachines of Paper and Wood
http://www.metafilter.com/108583/Machines%2Dof%2DPaper%2Dand%2DWood
<a href="http://toomai.wordpress.com/2011/03/19/building-a-computer-1-numerals/">Building a Computer 1: Numerals</a> - <em>recently my kids have been asking me about how computers work. I like to give in-depth answers to such questions, so we set out on a quest to understand how they work...</em> Follow-up parts <a href="http://toomai.wordpress.com/2011/03/31/building-a-computer-10-more-binary/" title="More Binary">2</a> <a href="http://toomai.wordpress.com/2011/04/03/building-a-computer-11-machines-of-paper/" title="Machines of Paper">3</a> <a href="http://toomai.wordpress.com/2011/04/04/building-a-computer-100-one-bit-prototype-with-data/" title="One Bit Prototype With Data">4</a> <a href="http://toomai.wordpress.com/2011/04/05/building-a-computer-101-wandels-toggle/" title="Wandel's Toggle">5</a> <a href="http://toomai.wordpress.com/2011/04/07/building-a-computer-110-the-elements-of-computing-systems/" title="The Elements of Computing Systems">6</a> <a href="http://toomai.wordpress.com/2011/04/14/building-a-computer-111-negative-numbers/" title="Negative Numbers">7</a> <a href="http://toomai.wordpress.com/2011/04/16/building-a-computer-1000-subtraction/" title="Subtraction">8</a> <a href="http://toomai.wordpress.com/2011/04/24/building-a-computer-1001-video-of-our-one-bit-adder-prototype/" title="Video of our One-Bit Adder Prototype">9</a> <a href="http://toomai.wordpress.com/2011/04/30/building-a-computer-1010-counting-and-human-versus-machine-error/" title="Counting and Human Versus Machine Error">10</a> <a href="http://toomai.wordpress.com/2011/05/13/building-a-computer-1011-computer-assisted-design/" title="Computer Assisted Design">11</a> <a href="http://toomai.wordpress.com/2011/05/15/building-a-computer-1100-multiplication-and-subtraction-with-an-adder/" title="Multiplication and Subtraction with an Adder">12</a> <a href="http://toomai.wordpress.com/2011/05/16/building-a-computer-1101-signal-split/" title="Signal Split">13</a> <a href="http://toomai.wordpress.com/2011/05/25/building-a-computer-1110-video-of-the-4-bit-adder/" title="Video of the 4-Bit Adder">14</a> <a href="http://toomai.wordpress.com/2011/06/04/building-a-computer-1111-video-of-our-signal-split-prototype/" title="Video of our Signal Split Prototype">15</a>. tag:metafilter.com,2011:site.108583Thu, 20 Oct 2011 11:49:40 -0800WolfdogThere's definitely a method to my madness. Definitely.
http://www.metafilter.com/67577/Theres%2Ddefinitely%2Da%2Dmethod%2Dto%2Dmy%2Dmadness%2DDefinitely
Lightning calculator and "mathemagician" <a href="http://blog.ted.com/2007/12/arthur_benjamin.php">Art Benjamin</a> goes through his paces in a 15 minute video. tag:metafilter.com,2007:site.67577Wed, 19 Dec 2007 07:37:01 -0800WolfdogLet's Party Like It's MCMXCIX
http://www.metafilter.com/54037/Lets%2DParty%2DLike%2DIts%2DMCMXCIX
<a href="http://scienceblogs.com/goodmath/2006/08/roman_numerals_and_arithmetic.php">Roman Numerals and Arithmetic</a> tag:metafilter.com,2006:site.54037Sat, 19 Aug 2006 04:30:40 -0800jack_moIncan Binary!
http://www.metafilter.com/26568/Incan%2DBinary
<a href="http://news.independent.co.uk/world/science_medical/story.jsp?story=418049">The Incas had binary!</a> Archaeologists have long known that <a href="http://www.angelfire.com/mo/zdawg/Khipu/Khipu.html">khipu strings</a> were used by the incas to store arithmetic records. Now, it's believed that they used a 7-bit binary code to store all kinds of "written" information. Well? Who's going to be the first to translate Harry Potter onto a khipu string? tag:metafilter.com,2003:site.26568Mon, 23 Jun 2003 06:40:55 -0800unreasonTests show U.S. children lag behind
http://www.metafilter.com/6772/Tests%2Dshow%2DUS%2Dchildren%2Dlag%2Dbehind
<a href="http://www.nandotimes.com/nation/story/0,1038,500470395-500720252-504019620-0,00.html">Tests show U.S. children lag behind</a> A careful reading of this page reveals that for many of America's schools, children lag behind some 16 other countries in math and in science. However: not all states contributred data. But the important thing is that a few schools and areas were right up there with the best in the world.
Perhaps then we ought to study those that work instead of bashing our educational system in general. tag:metafilter.com,2001:site.6772Wed, 04 Apr 2001 09:43:39 -0800Postroad